Crispy Onion Chicken Sandwich

Featured in: Pan & Griddle Cooking

This mouthwatering sandwich combines buttermilk-marinated fried chicken thighs with golden crispy fried onions and homemade garlic aioli, all served on soft brioche buns. The chicken marinates for up to 4 hours to ensure tenderness, then is breaded and fried until golden brown. Crispy onion strings are fried separately for maximum crunch, while a simple aioli brings creamy garlic flavor. Assemble with lettuce for added freshness. Perfect for a satisfying main course that serves four.

Updated on Sun, 18 Jan 2026 15:34:00 GMT
Golden fried chicken thigh layered on a soft brioche bun with crispy onion rings and creamy aioli. Save
Golden fried chicken thigh layered on a soft brioche bun with crispy onion rings and creamy aioli. | cozymsemen.com

The smell of frying onions always pulls me back to a Saturday afternoon when I'd promised myself I'd try something other than my usual grilled chicken routine. I had buttermilk leftover from biscuits, a bag of onions going soft, and a craving I couldn't name. What came out of that kitchen wasn't planned, but it was exactly what I needed. That first bite, with the crunch giving way to tender, tangy chicken, taught me that sometimes the best meals come from using what you have and trusting your instincts.

I made this for a friend who'd had a rough week, and watching her close her eyes after the first bite reminded me why I love cooking for people. She didn't say much at first, just kept eating, then finally looked up and said it tasted like comfort with a crunch. We sat on the porch with paper towels as napkins, and I realized this sandwich had become my go to for when words aren't enough but food can say everything.

Ingredients

  • Boneless, skinless chicken thighs: Thighs stay juicy even if you slightly overcook them, and they soak up the buttermilk marinade better than breasts ever could.
  • Buttermilk: This is what tenderizes the chicken and adds that subtle tang that makes fried chicken taste like it came from someone's grandmother's kitchen.
  • Garlic powder and paprika: These season the marinade so the flavor goes all the way through, not just on the surface.
  • All purpose flour and cornstarch: The cornstarch makes the coating extra crispy and light, not dense or gummy like flour alone can be.
  • Smoked paprika: It adds a hint of depth and warmth to the breading without making it spicy.
  • Yellow onion: Thinly sliced and fried until golden, these turn sweet and shatteringly crisp, adding a layer you won't want to skip.
  • Mayonnaise: The base of the aioli, and honestly, the glue that holds all the flavors together on the bun.
  • Garlic clove, lemon juice, and Dijon mustard: These three turn plain mayo into something bright, tangy, and way more interesting.
  • Brioche buns: Soft, slightly sweet, and sturdy enough to hold up to all the juicy, crispy layers without falling apart in your hands.
  • Vegetable oil: For frying, and you need enough to get a good sizzle going so everything crisps up instead of absorbing grease.

Instructions

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Marinate the chicken:
Whisk the buttermilk with garlic powder, paprika, salt, and pepper until it smells savory and inviting. Coat each chicken thigh completely, then cover and let it sit in the fridge for at least 30 minutes so the flavors sink in and the meat softens.
Prepare the breading:
In a shallow dish, combine the flour, cornstarch, smoked paprika, salt, and pepper. This dry mixture is what will give you that golden, crunchy crust you're after.
Coat the onions:
Toss your thinly sliced onions with flour, salt, and pepper until every piece is lightly dusted. They'll fry up into crispy, golden tangles that add so much texture to the sandwich.
Fry the onions:
Heat about an inch of oil in a large skillet to 350°F, then fry the onions in small batches for 2 to 3 minutes until they're crisp and amber. Drain them on paper towels and try not to eat them all before assembly.
Bread the chicken:
Pull each thigh from the marinade, let the excess drip off, then press it firmly into the breading mixture on both sides. The goal is a thick, even coat that will crisp up beautifully.
Fry the chicken:
Slide the breaded thighs into the hot oil and fry for 5 to 7 minutes per side until the crust is deep golden and the inside reaches 165°F. Let them rest on a wire rack so they stay crispy instead of steaming on a plate.
Make the aioli:
Stir together the mayo, minced garlic, lemon juice, Dijon, salt, and pepper until smooth and tangy. Taste it and adjust the lemon or garlic 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 makes a difference.
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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Close-up of a juicy Crispy Onion Chicken Sandwich with melted butter on toasted buns and fresh lettuce. Save
Close-up of a juicy Crispy Onion Chicken Sandwich with melted butter on toasted buns and fresh lettuce. | cozymsemen.com

The first time I served these sandwiches at a small gathering, I watched people go quiet while they ate, then come back for seconds without saying a word. Later, someone told me it reminded them of a diner they used to love, and I realized this sandwich had become more than just dinner. It was a little piece of comfort I could share, and that felt like the best kind of cooking.

How to Get the Crispiest Coating

The secret is in letting the breaded chicken sit for a few minutes before frying so the coating can set and adhere better. I also learned to press the breading firmly into the chicken with my palms, making sure there are no bare spots. If you want even more crunch, dip the chicken back into the buttermilk after the first dredge, then coat it again in the breading for a thicker crust. It's a little extra work, but the payoff is a shell that shatters when you bite into it.

Making It Your Own

This sandwich is forgiving and loves a little creativity. I've added a drizzle of hot honey over the chicken for a sweet heat combo that's become a favorite. Sometimes I swap the lettuce for tangy coleslaw or add pickles for extra brine and crunch. If you're not a fan of garlic aioli, try a spicy mayo with sriracha or a smoky chipotle version. The bones of this recipe are solid, so feel free to play around with toppings and sauces until it feels like yours.

Storing and Reheating

Fried chicken is best fresh, but leftovers can be stored in the fridge for up to two days. To reheat, skip the microwave and use your oven at 375°F for about 10 minutes to bring back some of that crispiness. The onions lose their crunch pretty quickly, so I always make them fresh if I'm reheating. The aioli keeps well in an airtight container for up to a week, and honestly, it's great on just about anything.

  • Store fried chicken and onions separately to keep textures intact.
  • Reheat on a wire rack in the oven to avoid sogginess.
  • Assemble sandwiches right before serving for the best experience.
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Homemade Crispy Onion Chicken Sandwich served with pickles and golden fried onions on a rustic plate. Save
Homemade Crispy Onion Chicken Sandwich served with pickles and golden fried onions on a rustic plate. | cozymsemen.com

This sandwich has earned its place in my regular rotation, not because it's fancy, but because it delivers every single time. Whether you're feeding yourself after a long day or impressing someone you care about, it just works.

Recipe FAQs

How long should the chicken marinate?

Marinate the chicken for at least 30 minutes, though up to 4 hours yields more flavorful, tender results. This allows the buttermilk to penetrate the meat fully.

Can I use chicken breasts instead of thighs?

Yes, boneless skinless chicken breasts work well as a substitute. They cook faster, so reduce frying time to 3-5 minutes per side depending on thickness to avoid drying out.

What's the best way to keep the crispy onions crunchy?

Fry onions just before assembling and drain them thoroughly on paper towels. Add them to the sandwich immediately before serving to prevent them from absorbing moisture from the aioli.

How do I achieve the perfect oil temperature for frying?

Heat oil to 350°F (175°C) using a thermometer for accuracy. This temperature crisps the exterior while cooking the interior without burning. Maintain temperature between batches by allowing oil to reheat.

Can I make the aioli ahead of time?

Absolutely. The aioli can be prepared up to 2 days in advance and refrigerated in an airtight container. Stir before using and adjust seasoning if needed.

What sides pair well with this sandwich?

Pickles, coleslaw, and french fries complement this sandwich beautifully. The pickles and slaw add refreshing crunch and acidity that balances the rich, fried components.

Crispy Onion Chicken Sandwich

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

Prep Time
25 min
Time to Cook
25 min
Total Duration
50 min
By Cozy Msemen Daniel Crawford


Skill Level Medium

Cuisine American

Output 4 Portions

Diet Info None specified

What You 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 black pepper to taste

Assembly

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

How-To Steps

Step 01

Prepare Buttermilk Marinade: Whisk together buttermilk, garlic powder, paprika, salt, and black pepper in a bowl. Submerge chicken thighs, ensuring complete coverage. Cover and refrigerate for minimum 30 minutes up to 4 hours.

Step 02

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

Step 03

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

Step 04

Fry Crispy Onions: Heat 1 inch of vegetable oil in a large skillet to 350°F. Working in batches, fry onions for 2-3 minutes until golden and crisp. Transfer to paper towels for drainage.

Step 05

Bread Chicken Thighs: Remove chicken from marinade, allowing excess buttermilk to drip off. Dredge each thigh in breading mixture, pressing firmly to ensure adhesion.

Step 06

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

Step 07

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

Step 08

Toast Brioche Buns: Optional: Butter and toast brioche buns in skillet until golden brown on cut sides.

Step 09

Assemble Sandwiches: Spread aioli on both cut sides of each bun. Layer with lettuce if desired, fried chicken thigh, generous portion of crispy onions, and top bun.

Tools Needed

  • Mixing bowls
  • Large skillet or deep fryer
  • Kitchen tongs
  • Wire rack or paper towels
  • Sharp knife and cutting board

Allergy Details

Please check every ingredient for allergens and reach out to your healthcare provider with concerns.
  • Contains eggs from mayonnaise
  • Contains wheat from flour and brioche buns
  • Contains milk from buttermilk and butter
  • Contains mustard from Dijon mustard
  • Brioche buns may contain soy and other allergens; verify packaging

Nutrition Info (per serving)

Nutritional info is an estimate. Cozy Msemen recommends asking a professional about your needs.
  • Calories: 670
  • Fats: 32 g
  • Carbohydrates: 61 g
  • Proteins: 32 g