Crispy Onion Chicken Sandwich (Printable)

Buttermilk-marinated fried chicken, crunchy fried onions, and creamy aioli stacked on soft brioche.

# 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 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 lemon juice
20 - ½ teaspoon Dijon mustard
21 - Salt and black pepper to taste

→ Assembly

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

# Directions:

01 - 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.
02 - In a shallow dish, combine flour, cornstarch, smoked paprika, salt, and black pepper for the breading mixture.
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 until golden and crisp, approximately 2 to 3 minutes per batch. 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 proper adhesion.
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 excess oil.
07 - In a small bowl, combine mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper to create the aioli sauce.
08 - Butter brioche buns and toast in a skillet until golden brown on both sides.
09 - Spread aioli on both sides of each bun. Layer with lettuce if desired, followed by fried chicken, generous mound of crispy onions, and top with bun half.

# Helpful Hints:

01 -
  • The buttermilk marinade keeps the chicken incredibly tender and adds a subtle tang that balances the richness.
  • Crispy fried onions bring a sweet crunch that turns a good sandwich into an unforgettable one.
  • The homemade aioli is so simple but tastes miles better than anything from a bottle.
  • Everything can be prepped ahead, so assembly is quick when hunger strikes.
02 -
  • Don't skip the buttermilk soak, it makes all the difference between dry chicken and juicy, flavorful meat.
  • Keep the oil temperature steady at 350°F, too hot and the breading burns before the chicken cooks, too cool and it gets greasy.
  • Press the breading firmly onto the chicken so it doesn't slide off in the oil.
  • Fry the onions in small batches so they cook evenly and stay crisp instead of steaming.
03 -
  • Pound the chicken thighs to an even thickness before marinating so they cook at the same rate and stay tender.
  • Add a splash of the buttermilk marinade to the breading and mix it in with your fingers to create craggy bits that fry up extra crispy.
  • Let the fried chicken rest on a wire rack instead of paper towels so air circulates and the bottom stays crisp.
  • Toast the buns cut side down in the residual oil from frying for a buttery, golden crunch.
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