Crispy Onion Chicken Sandwich

Featured in: Weekend Rustic Recipes

This mouthwatering sandwich features tender buttermilk-marinated chicken thighs, fried until golden and crispy. Layer it with homemade crispy fried onions and a tangy garlic aioli spread on toasted brioche buns for an unforgettable meal.

The key to success is marinating the chicken for at least 30 minutes to enhance tenderness and flavor. Frying both the onions and chicken at 350°F ensures perfectly crispy exteriors. This sandwich serves 4 and takes about 50 minutes total.

Updated on Sun, 18 Jan 2026 12:19:00 GMT
Golden fried chicken thighs piled high with crispy fried onions and creamy garlic aioli on a toasted brioche bun. Save
Golden fried chicken thighs piled high with crispy fried onions and creamy garlic aioli on a toasted brioche bun. | olivebriar.com

My neighbor knocked on my door one Saturday holding a grease-stained paper bag that smelled like heaven. Inside was this sandwich, still warm, from a food truck she'd found downtown. I took one bite and spent the next week trying to crack the code in my own kitchen. The crunch, the tang, the way the onions shattered against your teeth—it all felt like a delicious puzzle I had to solve.

I made this for my brother's birthday last summer, and he ate two in one sitting, which is saying something because he's the pickiest eater I know. We sat on the back porch with napkins piled up like snowdrifts, laughing at how ridiculous we looked trying to keep the onions from falling everywhere. He still texts me asking when I'm making them again.

Ingredients

  • Boneless, skinless chicken thighs: Thighs stay juicy even if you fry them a minute too long, and they have enough fat to keep the meat from drying out under all that crispy coating.
  • Buttermilk: This is what tenderizes the chicken and gives it that subtle tang; if you don't have it, mix regular milk with a tablespoon of lemon juice and let it sit for five minutes.
  • Garlic powder and paprika: These build flavor right into the meat so every bite tastes seasoned, not just the outside.
  • All-purpose flour: The base of your breading, it crisps up beautifully and holds onto the cornstarch for extra crunch.
  • Cornstarch: This is the secret to that glass-like shatter when you bite into the crust; don't skip it.
  • Smoked paprika: Adds a gentle smokiness that makes people think you grilled the chicken even though you didn't.
  • Yellow onion: Slice it thin so it fries fast and gets crispy without burning; sweet onions work too if you want a milder flavor.
  • Mayonnaise: The creamy backbone of the aioli, it clings to the chicken and bun without sliding off.
  • Garlic clove: Fresh garlic makes the aioli taste alive; jarred minced garlic works in a pinch but lacks that sharp bite.
  • Lemon juice: Brightens the aioli and cuts through the richness of the fried chicken.
  • Dijon mustard: Just a little adds complexity and a hint of sharpness that balances the mayo.
  • Brioche buns: Soft, slightly sweet, and sturdy enough to hold all the layers without falling apart in your hands.
  • Vegetable oil: Use something neutral with a high smoke point like canola or peanut oil for frying.

Instructions

Marinate the chicken:
Whisk the buttermilk with garlic powder, paprika, salt, and pepper until it smells warm and inviting, then submerge the chicken thighs completely. Cover the bowl and let it sit in the fridge for at least thirty minutes, though a few hours makes them even more tender.
Prep the breading:
In a shallow dish, combine flour, cornstarch, smoked paprika, salt, and pepper, mixing until the spices are evenly distributed. This is your armor for the chicken, so make sure it's well seasoned.
Coat the onions:
Toss the thinly sliced onions with flour, salt, and pepper in a bowl, separating the rings as you go so each piece gets coated. They should look dusty and pale, ready to turn golden.
Fry the onions:
Heat about an inch of oil in a large skillet to 350°F, then drop in small handfuls of onions and fry until they're crispy and amber, about two to three minutes. Move them to paper towels and resist the urge to snack on them all before assembly.
Bread the chicken:
Pull each thigh from the marinade, let the excess buttermilk drip off, then press it firmly into the breading mixture on both sides. The coating should stick like a second skin.
Fry the chicken:
Slide the breaded thighs into the hot oil and fry for five to seven minutes per side until the crust is deep golden and the internal temperature hits 165°F. Let them rest on a wire rack so the bottoms stay crispy.
Make the aioli:
Whisk together mayo, minced garlic, lemon juice, Dijon, salt, and pepper until smooth and creamy. Taste it and adjust the lemon or garlic to your liking.
Toast the buns:
If you want, butter the cut sides of the brioche buns and toast them in a skillet until golden and fragrant. This step is optional but adds a nice texture contrast.
Assemble the sandwiches:
Spread aioli generously on both halves of each bun, then layer with lettuce if using, a fried chicken thigh, and a big pile of crispy onions. Press the top bun on gently and try not to crush everything.
Freshly assembled Crispy Onion Chicken Sandwich showing golden-brown breading and crunchy onion rings on soft bread. Pin it
Freshly assembled Crispy Onion Chicken Sandwich showing golden-brown breading and crunchy onion rings on soft bread. | olivebriar.com

The first time I nailed this recipe, I stood in the kitchen eating one over the sink like some kind of feral animal, grease running down my wrists. My husband walked in and just laughed, then grabbed his own and joined me. It's become our Sunday ritual now, and honestly, I think it's the onions that keep us coming back.

Choosing Your Chicken

Thighs are my default because they forgive mistakes and stay moist, but breasts work if you prefer white meat—just watch them closely because they dry out faster. If you use breasts, pound them to an even thickness so they cook evenly and don't end up raw in the middle and dry on the edges. I tried tenderloins once and they were fine but a little underwhelming, lacking that juicy richness thighs bring. Dark meat also has more flavor on its own, which means every bite tastes like something even before you add the toppings.

Getting the Crunch Right

The cornstarch in the breading is non-negotiable if you want that crispy, crackly crust that shatters when you bite down. I learned this after making a batch with just flour and being disappointed by how soft it turned. The buttermilk helps too because the moisture creates little pockets in the breading that puff up and crisp when they hit the hot oil. Make sure your oil is actually hot before you start frying; I use a thermometer now after ruining a batch by guessing and ending up with soggy, pale chicken.

Serving and Storing

These are best eaten the moment they come together, while the chicken is still warm and the onions are at peak crunch. If you need to make components ahead, fry the chicken and onions earlier in the day, then reheat the chicken in a 375°F oven for about ten minutes to recrisp the crust. Leftover fried chicken keeps in the fridge for two days and reheats surprisingly well, though the onions lose their magic after a few hours and are better made fresh.

  • Serve with dill pickles, coleslaw, or sweet potato fries for a full spread that feels like a backyard cookout.
  • If you want heat, stir hot sauce or sriracha into the aioli or dust the breading with cayenne pepper.
  • Swap the brioche for potato rolls or even toasted sourdough if that's what you have on hand.
Homemade Crispy Onion Chicken Sandwich with juicy buttermilk-marinated chicken, topped with creamy aioli and lettuce. Pin it
Homemade Crispy Onion Chicken Sandwich with juicy buttermilk-marinated chicken, topped with creamy aioli and lettuce. | olivebriar.com

This sandwich has a way of turning an ordinary weeknight into something worth remembering. Make it once and you'll understand why I can't stop talking about it.

Frequently Asked Questions

How long should I marinate the chicken?

Marinate the chicken for at least 30 minutes, though 2-4 hours is ideal for deeper flavor penetration. Don't exceed 4 hours as the acidic buttermilk can break down the meat texture.

Can I use chicken breasts instead of thighs?

Yes, chicken breasts work well as a leaner alternative. Monitor cooking time carefully—breasts typically require 4-6 minutes per side depending on thickness. Pound them to even thickness for uniform cooking.

What oil is best for frying?

Use vegetable, canola, or peanut oil with high smoke points (around 350°F/175°C). Avoid olive oil as it burns at lower temperatures. Change the oil between batches for cleaner results.

How do I keep the onions crispy?

Drain the fried onions thoroughly on paper towels immediately after frying. Store them in an airtight container at room temperature. Add them to the sandwich just before serving to maintain crispness.

Can I make the aioli ahead of time?

Absolutely. The aioli keeps refrigerated for up to 3 days. Mix mayonnaise, minced garlic, lemon juice, and Dijon mustard in advance and store in a sealed container until ready to assemble.

What sides pair well with this sandwich?

Serve alongside pickles, coleslaw, or crispy fries. The tangy and crunchy sides complement the rich, creamy sandwich perfectly. Jalapeño slices or hot sauce add an extra kick if desired.

Crispy Onion Chicken Sandwich

Buttermilk-marinated fried chicken topped with crunchy fried onions and garlic aioli on a soft brioche bun.

Prep Time
25 Minutes
Cook Time
25 Minutes
Total Time
50 Minutes


Difficulty: Medium

Cuisine: American

Yield: 4 servings

Dietary: None specified

Ingredients

Chicken & Marinade

01 4 boneless, skinless chicken thighs
02 1 cup buttermilk
03 1 teaspoon garlic powder
04 1 teaspoon paprika
05 ½ teaspoon salt
06 ½ teaspoon black pepper

Breading

01 1 cup all-purpose flour
02 ½ cup cornstarch
03 1 teaspoon smoked paprika
04 1 teaspoon salt
05 ½ teaspoon ground black pepper

Crispy Onions

01 1 large yellow onion, thinly sliced
02 ½ cup all-purpose flour
03 ½ teaspoon salt
04 ½ teaspoon black pepper
05 Vegetable oil for frying

Aioli

01 ½ cup mayonnaise
02 1 large garlic clove, minced
03 1 tablespoon lemon juice
04 ½ teaspoon Dijon mustard
05 Salt and pepper to taste

Assembly

01 4 brioche buns, sliced
02 Butter for toasting buns (optional)
03 Lettuce leaves (optional)

Instructions

Step 01

Prepare Chicken Marinade: In a mixing bowl, whisk together buttermilk, garlic powder, paprika, salt, and black pepper. Add chicken thighs, ensuring complete coating. Cover and refrigerate for at least 30 minutes or up to 4 hours.

Step 02

Mix Breading Mixture: In a shallow dish, combine flour, cornstarch, smoked paprika, salt, and black pepper. Set aside for dredging.

Step 03

Coat Onion Slices: In a separate bowl, toss sliced onions with flour, salt, and black pepper until evenly coated.

Step 04

Fry Onions: Heat 1 inch of vegetable oil in a large skillet to 350°F. Fry onions in batches for 2 to 3 minutes per batch until golden and crisp. Drain on paper towels.

Step 05

Bread Chicken: Remove chicken from marinade, allowing excess buttermilk to drip off. Dredge each thigh in the breading mixture, pressing gently to adhere.

Step 06

Fry Chicken: Fry chicken in the same hot oil for 5 to 7 minutes per side until cooked through and golden brown. Transfer to a wire rack or paper towels to drain.

Step 07

Prepare Aioli: In a small bowl, combine mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper. Mix until smooth.

Step 08

Toast Buns: If desired, butter brioche buns and toast in a skillet until golden on both sides.

Step 09

Assemble Sandwich: Spread aioli on both sides of each toasted bun. Layer with lettuce if desired, followed by fried chicken, a generous portion of crispy onions, and top bun. Serve immediately.

Tools You'll Need

  • Mixing bowls
  • Large skillet or deep fryer
  • Tongs
  • Wire rack or paper towels
  • Knife and cutting board

Allergy Information

Please check ingredients for potential allergens and consult a health professional if in doubt.
  • Contains eggs from mayonnaise
  • Contains wheat from flour and brioche buns
  • Contains milk from buttermilk and butter
  • Contains mustard in aioli
  • Brioche buns may contain soy or additional allergens; verify packaging

Nutrition Facts (Per Serving)

It is important to consider this information as approximate and not to use it as definitive health advice.
  • Calories: 670
  • Total Fat: 32 g
  • Total Carbohydrate: 61 g
  • Protein: 32 g