Crispy Onion Chicken Sandwich (Printable)

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

# 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 - 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 ground 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 fresh lemon juice
20 - ½ 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 Steps:

01 - Whisk together buttermilk, garlic powder, paprika, salt, and black pepper in a bowl. Submerge chicken thighs, ensuring complete coverage. Cover and refrigerate for minimum 30 minutes up to 4 hours.
02 - Combine flour, cornstarch, smoked paprika, salt, and black pepper in a shallow dish. Set aside for dredging.
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 onions for 2-3 minutes until golden and crisp. Transfer to paper towels for drainage.
05 - Remove chicken from marinade, allowing excess buttermilk to drip off. Dredge each thigh in breading mixture, pressing firmly to ensure adhesion.
06 - Fry breaded chicken in the same hot oil for 5-7 minutes per side until golden brown and cooked through. Transfer to wire rack or paper towels.
07 - Combine mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper in a small bowl. Mix until smooth and creamy.
08 - Optional: Butter and toast brioche buns in skillet until golden brown on cut sides.
09 - Spread aioli on both cut sides of each bun. Layer with lettuce if desired, fried chicken thigh, generous portion of crispy onions, and top bun.

# Expert Advice:

01 -
  • The buttermilk soak makes the chicken so tender you'll wonder why you ever skipped marinating before.
  • Crispy fried onions add a texture that turns a simple sandwich into something you'll crave all week.
  • The garlic aioli pulls everything together with a creamy tang that tastes like you spent way more effort than you actually did.
  • It's impressive enough for guests but forgiving enough for a weeknight when you just want something satisfying.
02 -
  • Don't skip the marinating time, even 30 minutes makes a huge difference in how juicy and flavorful the chicken turns out.
  • Keep your oil at a steady 350°F because too hot will burn the coating before the chicken cooks through, and too cool will make everything greasy.
  • Let the fried chicken rest on a wire rack, not paper towels, so air circulates and the bottom doesn't get soggy.
  • Make extra crispy onions because they disappear fast, and you'll want them for topping salads or snacking on while you cook.
03 -
  • Use a thermometer to monitor your oil temperature because guessing leads to uneven frying and disappointment.
  • Pat the chicken dry after marinating before breading so the coating sticks better and fries up crispier.
  • Double the crispy onions because they're addictive, and you'll wish you had more once they're gone.
  • Toast your buns even if you think you don't have time, it adds a buttery richness that makes the whole sandwich feel more complete.
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