Crispy Onion Chicken Sandwich (Printable)

Buttermilk-marinated fried chicken topped with crunchy fried onions and creamy aioli on a soft brioche bun.

# 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 - 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:

01 - In a mixing bowl, whisk together buttermilk, garlic powder, paprika, salt, and black pepper. Submerge chicken thighs ensuring full coverage. Cover and refrigerate for 30 minutes minimum, up to 4 hours.
02 - Combine flour, cornstarch, smoked paprika, salt, and black pepper in a shallow dish. Set aside for dredging.
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 onions for 2-3 minutes until golden and crispy. Transfer to paper towels to drain.
05 - Remove chicken from marinade, allowing excess buttermilk to drip away. Dredge each thigh thoroughly in breading mixture, pressing gently to ensure adhesion.
06 - Fry breaded chicken in the same oil for 5-7 minutes per side until golden brown and internal temperature reaches 165°F. Drain on a wire rack or paper towels.
07 - Whisk together mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper in a small bowl until smooth and emulsified.
08 - Optional: Butter and toast brioche buns in a skillet over medium heat until golden on both sides.
09 - Spread aioli on both cut sides of each brioche bun. Layer with lettuce if desired, followed by fried chicken thigh, a generous portion of crispy onions, and top half of bun.

# Expert Advice:

01 -
  • The buttermilk soak makes the chicken so tender it nearly falls apart at the first bite, yet the crust stays shatteringly crisp.
  • Homemade fried onions add a sweet, crunchy layer that no store-bought topping can match.
  • You control the heat, the salt, and the garlic, which means every sandwich tastes exactly how you want it.
  • It comes together in under an hour but tastes like you spent all day in the kitchen.
02 -
  • Do not skip the buttermilk marinade, even if you are in a hurry; 30 minutes makes a noticeable difference in tenderness.
  • Keep the oil temperature steady at 350°F, because too hot will burn the crust before the chicken cooks through, and too cool will make it greasy.
  • Fry the onions first and set them aside, so you can use the same oil for the chicken without switching pans.
  • Press the breading onto the chicken firmly, or it will fall off in the oil and leave you with bare patches.
03 -
  • Use a meat thermometer to check that the chicken reaches 165°F internally, so you never have to guess if it is done.
  • Let the fried chicken rest on a wire rack instead of paper towels to keep the bottom from getting soggy.
  • Make a double batch of the crispy onions because they disappear fast and are great on salads, burgers, or just eaten by the handful.
  • Toast the buns even if you think you do not have time; the texture difference is worth the extra two minutes.
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