Crispy Onion Chicken Sandwich (Print Version)

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

# Ingredient List:

→ 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 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 pepper to taste

→ Assembly

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

# Steps:

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 in a separate bowl 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 until golden and crispy. Transfer to paper towels to drain.
05 - Remove marinated chicken from refrigerator and allow excess buttermilk to drip off. Dredge each thigh in breading mixture, pressing firmly to ensure coating adheres.
06 - Fry breaded chicken in the same hot oil for 5-7 minutes per side until golden brown and cooked through. Transfer to a wire rack or paper towels to drain excess oil.
07 - Combine mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper in a small bowl and mix until smooth.
08 - Optionally butter and toast brioche buns in a skillet over medium heat until lightly golden on cut sides.
09 - Spread aioli on both cut sides of each bun. Layer with lettuce if desired, top with fried chicken thigh, add a generous portion of crispy onions, and close with bun top.

# Helpful Hints:

01 -
  • The buttermilk marinade keeps the chicken so tender you barely need to chew, while the double coating delivers that shatteringly crisp crust.
  • Homemade crispy onions add a sweet, crunchy layer that store-bought versions can't touch.
  • The garlicky aioli ties everything together without overpowering the chicken's flavor.
  • It's a weekend project that feels special but doesn't demand any fancy equipment or hard-to-find ingredients.
02 -
  • Don't skip the marinade time; rushing it leaves the chicken bland and tougher than it should be.
  • Keep the oil temperature steady at 350°F; too cool and the coating absorbs grease, too hot and it burns before the chicken cooks through.
  • Let the fried chicken rest on a wire rack instead of paper towels so the bottom crust stays crisp.
  • Slice the onions as thin as you can manage; uneven thickness means some pieces burn while others stay limp.
03 -
  • Use a thermometer to monitor oil temperature; guessing leads to uneven frying and greasy results.
  • Press the breading onto the chicken firmly so it doesn't fall off in the oil.
  • Double the onions because they vanish faster than you'd expect, and having extra never hurts.
  • Let the chicken rest for a minute after frying so the juices redistribute and the crust sets properly.
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