Crispy Onion Chicken Sandwich (Printable view)

Buttermilk fried chicken with crispy onions and garlic aioli on brioche. A satisfying American classic in 50 minutes.

# 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

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 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:

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, up to 4 hours.
02 - Combine flour, cornstarch, smoked paprika, salt, and black pepper in a shallow dish and set aside.
03 - 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 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 gently to adhere. Fry in the hot oil for 5–7 minutes per side until cooked through and golden brown. Transfer to a wire rack or paper towels.
06 - Combine mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper in a small bowl and mix until smooth.
07 - Butter brioche buns and toast in a skillet over medium heat until golden brown on both sides.
08 - Spread aioli on both sides of each toasted bun. Layer with lettuce, fried chicken, and a generous mound of crispy onions. Cap with the top bun and serve immediately.

# Expert Advice:

01 -
  • The buttermilk marinade keeps the chicken ridiculously tender while the double coating gets shatteringly crisp.
  • Those fried onions add a sweet, crunchy contrast that makes every bite different.
  • The garlic aioli ties everything together with just enough tang to balance the richness.
  • You can prep the components ahead and assemble right before serving so it stays hot and crispy.
02 -
  • Don't skip the marinating time, even 30 minutes makes a noticeable difference in how juicy the chicken stays after frying.
  • Keep the oil temperature steady at 350°F because too hot burns the crust before the chicken cooks through, and too cool makes it greasy.
  • Press the breading onto the chicken firmly so it sticks well and doesn't fall off in the oil.
  • Fry the onions in small batches so they crisp up evenly instead of steaming each other.
03 -
  • Use a thermometer to monitor your oil temp, it's the single biggest factor in getting the crust right.
  • Let the chicken rest on a wire rack after frying, not paper towels, so the bottom doesn't steam and soften.
  • Double the onions because they disappear fast and everyone will want more.
  • Press the breading into the chicken with your palms, not just a light dip, so it really adheres and creates that thick crust.
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