Crispy Onion Chicken Sandwich

Featured in: Weeknight Dinners

This mouthwatering sandwich combines buttermilk-marinated chicken thighs, fried until golden and crispy, with a generous layer of homemade crispy fried onions and creamy garlic aioli. The chicken marinates for at least 30 minutes to ensure tenderness, then gets breaded and fried to perfection. The onions are fried separately until they're golden and crunchy. Everything comes together on a soft brioche bun with optional lettuce for freshness.

Updated on Sun, 18 Jan 2026 11:31:00 GMT
Golden-brown Crispy Onion Chicken Sandwich on a toasted brioche bun, stacked high with juicy fried chicken and crispy fried onions.  Save
Golden-brown Crispy Onion Chicken Sandwich on a toasted brioche bun, stacked high with juicy fried chicken and crispy fried onions. | brilliantcrust.com

My cousin showed up one Saturday with a craving she couldn't shake: fried chicken on a bun, but not just any version. She wanted crunch on crunch, something that crackled with every bite. We didn't have a recipe, just hunger and a hunch that piling crispy onions on top of golden chicken would be the answer. That afternoon, we turned my tiny kitchen into a frying station, and by the time we sat down with those towering sandwiches, we knew we'd stumbled onto something worth repeating.

I made these sandwiches for a small backyard gathering last summer, and they disappeared faster than anything else on the table. People kept asking what the secret was, and honestly, it's just layering textures and not being shy with the onions. One friend came back for seconds before I'd even finished assembling the last bun. That's when I knew this recipe had earned its spot in my regular rotation.

Ingredients

  • Boneless, skinless chicken thighs: Thighs stay juicier than breasts and handle the marinade beautifully, plus they fry up with more flavor.
  • Buttermilk: This is what makes the chicken impossibly tender and helps the breading stick like glue.
  • Garlic powder and paprika: These add warmth and a subtle smokiness to the marinade without overpowering the chicken.
  • All-purpose flour and cornstarch: The combo creates a lighter, crispier crust than flour alone ever could.
  • Smoked paprika: A little goes a long way, giving the breading a gentle char flavor that makes people think you grilled it.
  • Yellow onion: Slice it thin so it fries up shatteringly crisp, almost like savory onion straws.
  • Mayonnaise: The base for a quick aioli that tastes way fancier than the effort required.
  • Garlic clove, minced: Fresh garlic in the aioli makes all the difference, sharp and aromatic.
  • Lemon juice: Brightens up the richness and keeps the aioli from feeling too heavy.
  • Dijon mustard: Just a touch adds tang and helps emulsify the aioli into something silky.
  • Brioche buns: Soft, slightly sweet, and sturdy enough to hold all that crunch without falling apart.
  • Vegetable oil: For frying, you need something with a high smoke point that won't interfere with the flavors.

Instructions

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Marinate the chicken:
Whisk together the buttermilk, garlic powder, paprika, salt, and pepper, then submerge the chicken thighs completely. Let them soak in the fridge for at least 30 minutes, though a few hours makes them even more tender.
Prepare the breading:
Combine flour, cornstarch, smoked paprika, salt, and pepper in a shallow dish and mix well. This dry mixture will give you that shatteringly crisp coating.
Coat the onions:
Toss your thinly sliced onions with flour, salt, and pepper until every piece is lightly dusted. Shake off any excess so they fry up light and crispy.
Fry the onions:
Heat about an inch of oil to 350°F and fry the onions in small batches for 2 to 3 minutes until golden. Drain them on paper towels and try not to sneak too many before assembly.
Bread the chicken:
Pull the chicken from the marinade, let the excess drip off, then press each thigh firmly into the breading mixture. Make sure every inch is coated for maximum crunch.
Fry the chicken:
Slide the breaded thighs into the hot oil and fry for 5 to 7 minutes per side until deep golden brown and cooked through. Let them rest on a wire rack so they stay crispy.
Make the aioli:
Stir together mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper until smooth. Taste and adjust the seasoning to your liking.
Toast the buns:
If you want extra richness, butter the cut sides of the brioche buns and toast them in a skillet until golden. It's optional, but it adds another layer of flavor.
Assemble the sandwiches:
Spread aioli generously on both halves of each bun, then layer with lettuce if using, a piece of fried chicken, a big pile of crispy onions, and the top bun. Press down gently and get ready for the crunch.
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Slice meats, cheeses, and bread evenly for sandwiches, charcuterie boards, and precise meal prep.
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Homemade Crispy Onion Chicken Sandwich served with creamy aioli on a soft bun, featuring golden fried onions and tender chicken.  Save
Homemade Crispy Onion Chicken Sandwich served with creamy aioli on a soft bun, featuring golden fried onions and tender chicken. | brilliantcrust.com

The first time I packed one of these sandwiches for lunch the next day, I wasn't sure how it would hold up. But even cold, that crunch was still there, and the aioli had soaked into the bun just enough to make it taste even better. It reminded me that some recipes are flexible, forgiving, and delicious no matter when or how you eat them.

Storing and Reheating

If you have leftovers, store the fried chicken and onions separately from the buns and aioli so nothing gets soggy. The chicken reheats beautifully in a 375°F oven for about 10 minutes, and the onions can be crisped back up in a hot skillet for a minute or two. Assemble fresh sandwiches when you're ready to eat, and they'll taste almost as good as the first time.

Customizing Your Sandwich

This recipe is a great base for experimenting with flavors you love. Add a drizzle of hot sauce to the aioli if you want heat, or swap in pickled jalapeños for a tangy kick. Some people like a handful of coleslaw on top for extra crunch and freshness, and I've even seen someone add a slice of sharp cheddar, which melted slightly from the heat of the chicken. Play around and make it your own.

Serving Suggestions

These sandwiches are filling enough to stand on their own, but a side of crispy fries or a simple green salad balances out the richness. I like serving them with dill pickles on the side, something about that vinegary crunch just works. If you're feeding a crowd, set up a toppings bar with extra aioli, hot sauce, and pickles so everyone can build their perfect bite.

  • Pair with sweet potato fries for a slightly sweet contrast.
  • Serve alongside a tangy coleslaw to cut through the richness.
  • Offer extra aioli and hot sauce on the side for those who want more flavor.
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Close-up of Crispy Onion Chicken Sandwich with melted aioli, crunchy onion topping, and juicy fried chicken on a toasted brioche bun. Save
Close-up of Crispy Onion Chicken Sandwich with melted aioli, crunchy onion topping, and juicy fried chicken on a toasted brioche bun. | brilliantcrust.com

There's something deeply satisfying about biting into a sandwich that crunches this loudly. It's messy, it's indulgent, and it's worth every napkin you'll need.

Recipe Q&A

Can I use chicken breasts instead of thighs?

Yes, you can substitute chicken breasts for thighs. However, reduce the cooking time to 4-5 minutes per side to prevent drying out the meat. Thighs are naturally juicier and more forgiving.

How long can the chicken marinate?

The chicken should marinate for at least 30 minutes, but can be refrigerated in the buttermilk mixture for up to 4 hours. Don't marinate longer than 4 hours as the acid in the buttermilk can make the meat mushy.

What oil temperature is best for frying?

Maintain the oil at 350°F (175°C) for optimal results. Use a thermometer to monitor temperature. This ensures the breading crisps up while the chicken cooks through without absorbing excess oil.

How do I keep the onions crispy?

Fry the onions separately from the chicken to maintain their crispness. Drain them on paper towels immediately after frying and season while warm. Add them to the sandwich just before serving to prevent sogginess.

Can I make the aioli ahead of time?

Yes, prepare the aioli up to 2 days in advance. Store it in an airtight container in the refrigerator. The flavors will actually deepen over time, making it even more flavorful.

What sides pair well with this sandwich?

Serve with pickles, coleslaw, or fries for a complete meal. The tangy pickles and cool slaw complement the rich, crispy sandwich perfectly.

Crispy Onion Chicken Sandwich

Buttermilk-marinated fried chicken with crispy onions and garlic aioli served on toasted brioche.

Time to prep
25 min
Time to cook
25 min
Overall time
50 min
Created by Isabella Davis


Skill level Medium

Culinary roots American

Makes 4 Number of servings

Diet considerations None specified

What you'll need

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 fresh 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

How To Make It

Step 01

Prepare buttermilk marinade: In a 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

Combine dry breading mixture: In a shallow dish, mix flour, cornstarch, smoked paprika, salt, and black pepper.

Step 03

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

Step 04

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

Step 05

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

Step 06

Fry the 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 garlic aioli: In a small bowl, combine mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper.

Step 08

Toast brioche buns: Butter and toast brioche buns in a skillet until golden brown, optional step.

Step 09

Assemble sandwiches: Spread aioli on both sides of each bun. Layer with lettuce if using, fried chicken, a generous portion of crispy onions, and top with the bun.

What you'll need

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

Allergy notice

Check each ingredient for allergens and get medical advice if you're unsure.
  • Contains eggs in mayonnaise
  • Contains wheat in flour and brioche buns
  • Contains milk in buttermilk and butter
  • Contains mustard in aioli
  • Brioche buns may contain soy or other allergens—verify labels if needed

Nutritional info (per serving)

Nutrition info is meant to guide only—it's not a replacement for professional medical input.
  • Calories: 670
  • Fats: 32 g
  • Carbohydrates: 61 g
  • Proteins: 32 g