Crispy Onion Chicken Sandwich (Printable)

Buttermilk-marinated fried chicken with crispy onions, garlic aioli, and brioche bun. A savory American classic.

# What You’ll 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 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 Prepare:

01 - In a bowl, whisk together buttermilk, garlic powder, paprika, salt, and black pepper. Add chicken thighs, ensuring full coverage. Cover and refrigerate for at least 30 minutes, 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. Fry onions in batches for 2-3 minutes per batch until golden and crispy. Drain on paper towels.
05 - Remove chicken from marinade, allowing excess buttermilk to drip off. Dredge each thigh in the breading mixture, pressing firmly to adhere.
06 - 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.
07 - In a small bowl, combine mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper.
08 - Butter and toast brioche buns in a skillet until golden brown.
09 - Spread aioli on both sides of each bun. Layer with lettuce, fried chicken, and crispy onions. Top with bun half and serve immediately.

# Expert Suggestions:

01 -
  • The buttermilk marinade keeps the chicken so tender you can cut it with a fork.
  • Crispy fried onions add a texture that makes every bite feel like a celebration.
  • The garlic aioli ties everything together with a creamy, tangy punch.
  • It feels like restaurant quality but costs a fraction of takeout.
02 -
  • Don't skip the cornstarch in the breading, it's what makes the coating stay crispy instead of turning soft and sad.
  • Fry the onions in small batches or they'll steam instead of crisp, and you'll lose that addictive crunch.
  • Use a thermometer to keep the oil at 350°F, too hot and the outside burns before the chicken cooks, too cool and it turns greasy.
  • Let the fried chicken rest on a wire rack, not paper towels, so the bottom stays crispy while it drains.
03 -
  • Make extra crispy onions and store them in an airtight container, they stay crunchy for a day and are amazing on salads or burgers.
  • If you don't have buttermilk, mix regular milk with a tablespoon of lemon juice or vinegar and let it sit for five minutes.
  • Press the chicken firmly into the breading and let it sit for a minute before frying so the coating sticks better.
  • Assemble the sandwiches right before serving, because the steam from the hot chicken will soften the bun if it sits too long.
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