Crispy Onion Chicken Sandwich (Printable)

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

# 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

07 - 1 cup all-purpose flour
08 - ½ cup cornstarch
09 - 1 teaspoon smoked paprika
10 - 1 teaspoon salt
11 - ½ teaspoon ground black pepper

→ Crispy Onions

12 - 1 large yellow onion, thinly sliced
13 - ½ cup all-purpose flour
14 - ½ teaspoon salt
15 - ½ teaspoon black pepper
16 - Vegetable oil for frying

→ Aioli

17 - ½ cup mayonnaise
18 - 1 large garlic clove, minced
19 - 1 tablespoon fresh lemon juice
20 - ½ teaspoon Dijon mustard
21 - Salt and pepper to taste

→ Assembly

22 - 4 brioche buns, sliced
23 - Butter for toasting buns
24 - Lettuce leaves

# How to Make It:

01 - Whisk together buttermilk, garlic powder, paprika, salt, and black pepper in a bowl. Add chicken thighs and coat thoroughly. Cover and refrigerate for at least 30 minutes or up to 4 hours.
02 - In a shallow dish, combine flour, cornstarch, smoked paprika, salt, and black pepper. Set aside.
03 - Toss sliced onions with flour, salt, and black pepper in a separate bowl until evenly coated.
04 - 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 crispy. Drain on paper towels.
05 - Remove chicken from marinade and allow excess buttermilk to drip off. Dredge each thigh in the breading mixture, pressing firmly to ensure coating adheres.
06 - 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.
07 - Combine mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper in a small bowl. Mix until smooth.
08 - Optional: Butter brioche buns and toast in a skillet over medium heat until golden.
09 - Spread aioli on both sides of each brioche bun. Layer with lettuce, fried chicken thigh, generous mound of crispy onions, and top with second bun half.

# Expert Advice:

01 -
  • The buttermilk soak keeps the chicken so tender you barely need to chew, and it fries up with the kind of crust that crackles when you bite in.
  • Crispy onions add a sweet, shattering crunch that makes every bite feel like a celebration instead of just dinner.
  • The garlicky aioli ties everything together without overpowering the chicken, and you can tweak it as spicy or mild as you like.
  • It comes together in under an hour, which feels like a miracle for something this satisfying and restaurant quality.
02 -
  • Don't skip the buttermilk marinade, even if you're in a hurry, because that's what keeps the chicken juicy and prevents it from turning rubbery.
  • Keep the oil temperature steady around 350°F or the breading will either burn or turn greasy and limp.
  • Let the fried chicken rest on a wire rack instead of paper towels so air circulates underneath and the crust stays crisp.
  • Fry the onions in small batches or they'll steam instead of crisping up, and you'll lose that shattering crunch.
03 -
  • Use a thermometer to check the oil temperature consistently, because even small fluctuations can ruin the texture of the breading.
  • Double the crispy onions and keep extras in an airtight container, they're incredible on salads, burgers, or even scrambled eggs the next morning.
  • If the chicken is browning too fast but not cooked through, lower the heat slightly and give it an extra minute or two per side.
  • Press the sandwich gently with your palm before cutting it in half, this helps everything settle and makes it easier to eat without losing toppings.
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