Crispy Onion Chicken Sandwich (Printable version)

Buttermilk-marinated fried chicken with crispy onions and garlic aioli on a soft brioche bun. Serves 4 in 50 minutes.

# Needed ingredients:

→ Chicken & Marinade

01 - 4 boneless, skinless chicken thighs
02 - 1 cup buttermilk
03 - 1 teaspoon garlic powder
04 - 1 teaspoon paprika
05 - 1/2 teaspoon salt
06 - 1/2 teaspoon black pepper

→ Breading

07 - 1 cup all-purpose flour
08 - 1/2 cup cornstarch
09 - 1 teaspoon smoked paprika
10 - 1 teaspoon salt
11 - 1/2 teaspoon ground black pepper

→ Crispy Onions

12 - 1 large yellow onion, thinly sliced
13 - 1/2 cup all-purpose flour
14 - 1/2 teaspoon salt
15 - 1/2 teaspoon black pepper
16 - Vegetable oil for frying

→ Aioli

17 - 1/2 cup mayonnaise
18 - 1 large garlic clove, minced
19 - 1 tablespoon fresh lemon juice
20 - 1/2 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

# How to make it:

01 - In a mixing 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. Working in batches, fry coated onions for 2-3 minutes per batch until golden and crispy. Transfer to paper towels to drain.
05 - Remove chicken from marinade, allowing excess buttermilk to drip off. Dredge each thigh in the breading mixture, pressing firmly to ensure adhesion.
06 - Fry breaded chicken in the hot oil for 5-7 minutes per side until internal temperature reaches 165°F and exterior is golden brown. Transfer to a wire rack or paper towels to drain.
07 - In a small bowl, whisk together mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper until combined.
08 - Optional step: Butter brioche buns and toast in a skillet over medium heat until golden.
09 - Spread aioli on both cut sides of each brioche bun. Layer with lettuce if desired, top with fried chicken thigh, generous portion of crispy onions, and close with top bun.

# Expert Suggestions:

01 -
  • The buttermilk marinade keeps the chicken so tender you can practically pull it apart with a fork.
  • Those crispy onions add a sweet crunch that makes every bite feel like a little celebration.
  • The garlic aioli ties everything together without overpowering the chicken.
  • You can have this on the table in under an hour, which feels like magic on a weeknight.
02 -
  • Don't skip the cornstarch in the breading, it's what makes the crust shatter instead of chew.
  • Let the chicken rest on a wire rack after frying so the bottom doesn't get soggy from trapped steam.
  • If your oil temperature drops too much between batches, the coating will absorb more oil and turn greasy.
  • Slice the onions as thin as you can manage, thicker pieces won't crisp up the same way.
03 -
  • Press the breading onto the chicken firmly with your hands, loose coating falls off in the oil.
  • Let the marinated chicken come to room temperature for 10 minutes before breading so it fries more evenly.
  • Use a spider strainer to flip the chicken instead of tongs, it gives you more control and doesn't knock off the crust.
  • If you're making a big batch, keep the finished chicken warm in a 200°F oven on a wire rack while you finish frying.
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