Crispy Onion Chicken Sandwich (Printable)

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

# Components:

→ 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 lemon juice
20 - 1/2 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

# Directions:

01 - In a bowl, whisk together buttermilk, garlic powder, paprika, salt, and black pepper. Add chicken thighs, ensuring they are fully coated. Cover and refrigerate for at least 30 minutes, or up to 4 hours.
02 - In a shallow dish, mix 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 well coated.
04 - Heat 1 inch of vegetable oil in a large skillet to 350°F. Fry onions in batches until golden and crisp, about 2-3 minutes per batch. Drain on paper towels.
05 - Remove chicken from marinade, allowing excess buttermilk to drip off. Dredge each thigh in the breading mixture, pressing to adhere. 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.
06 - In a small bowl, combine mayonnaise, garlic, lemon juice, Dijon mustard, salt, and pepper to make the aioli.
07 - Butter and toast brioche buns in a skillet until golden, if desired.
08 - Spread aioli on both sides of each bun. Layer with lettuce if using, fried chicken, a generous mound of crispy onions, and top with the bun.

# Expert Advice:

01 -
  • The buttermilk soak makes the chicken so tender it practically melts, while the cornstarch in the breading creates an audible crunch.
  • Homemade crispy onions taste nothing like the canned kind and take less effort than you think.
  • Everything can be prepped ahead, so you're not scrambling when everyone shows up hungry.
  • The aioli ties it all together without drowning out the chicken or onions.
02 -
  • Don't skip the marinating time; I tried once when I was in a hurry and the chicken was noticeably less tender and flavorful.
  • Keep the oil temperature steady around 350°F, because too hot and the breading burns before the chicken cooks, too cool and it turns greasy.
  • Fry the onions first so they stay crispy while you work on the chicken, and keep them in a warm oven if needed.
03 -
  • Press the breading onto the chicken firmly with your palms so it doesn't fall off in the oil, a trick I learned after losing half a coating once.
  • Use a wire rack instead of paper towels for draining so air circulates and the bottom doesn't get soggy.
  • Double the crispy onions because they disappear faster than you think, and you'll want extras for snacking.
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