Crispy Onion Chicken Sandwich (Printable)

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

# Ingredient List:

→ 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, optional
24 - Lettuce leaves, optional

# Steps:

01 - In a bowl, whisk together buttermilk, garlic powder, paprika, salt, and black pepper. 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 - In a separate bowl, toss sliced onions with flour, salt, and black pepper until evenly coated.
04 - Heat 1 inch of vegetable oil in a large skillet to 350°F. Fry onions in batches for 2-3 minutes per batch until golden and crisp. Drain on paper towels.
05 - Remove chicken from marinade, allowing excess buttermilk to drip off. Dredge each thigh in the breading mixture, pressing firmly to adhere.
06 - Fry chicken in the same hot oil for 5-7 minutes per side until cooked through and golden brown. Transfer to a wire rack or paper towels to drain.
07 - In a small bowl, combine mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper. Mix until smooth.
08 - Optional: Butter and toast brioche buns in a skillet until golden brown.
09 - Spread aioli on both sides of each bun. Layer with lettuce if desired, fried chicken, a generous mound of crispy onions, and top with bun half.

# Tips from the Pros:

01 -
  • The buttermilk marinade keeps the chicken unbelievably juicy while the double coating creates shatteringly crisp edges.
  • Those crispy onions add a sweet, crunchy contrast that makes every bite feel like a celebration.
  • The homemade aioli is so much better than plain mayo and takes about two minutes to whisk together.
  • Everything comes together in under an hour, making it perfect for weekend lunches or casual dinners with friends.
02 -
  • Keep the oil temperature steady at 350°F because too hot will burn the coating before the chicken cooks through, and too cool makes everything greasy.
  • Press the breading firmly onto the chicken after dredging so it stays put during frying instead of falling off in sad clumps.
  • Fry the onions in small batches so they cook evenly and stay crispy instead of steaming and getting soggy.
  • Let the chicken rest on a wire rack after frying, not paper towels, so the bottom stays crispy instead of getting damp.
03 -
  • Use a thermometer to monitor oil temperature because guessing leads to unevenly cooked chicken and frustration.
  • Marinate the chicken overnight if you can, the flavor deepens and the texture becomes even more tender.
  • Double the crispy onions because they disappear fast and you'll want extras for snacking or topping other dishes.
  • Toast the buns even if you think you don't have time, it makes a noticeable difference in texture and flavor.
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