Crispy Onion Chicken Sandwich (Printable)

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

# 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 - 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 It:

01 - In a mixing bowl, whisk together buttermilk, garlic powder, paprika, salt, and black pepper. Submerge chicken thighs ensuring complete coating. Cover and refrigerate for minimum 30 minutes or up to 4 hours.
02 - In a shallow dish, combine flour, cornstarch, smoked paprika, salt, and black pepper. 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 per batch until golden and crispy. Transfer to paper towels for drainage.
05 - Remove marinated chicken from refrigerator, allowing excess buttermilk to drip off. Dredge each thigh thoroughly in breading mixture, pressing gently to ensure adhesion.
06 - Fry breaded chicken thighs in the same hot oil for 5-7 minutes per side until golden brown and cooked through internally. Transfer to wire rack or paper towels to drain excess oil.
07 - In a small bowl, combine mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper. Mix until smooth and well incorporated.
08 - Optional step: Butter brioche buns and toast in skillet until light golden brown on cut sides.
09 - Spread aioli on both cut sides of each bun. Layer with optional lettuce, fried chicken thigh, generous portion of crispy onions, and top with bun. Serve immediately.

# Expert Tips:

01 -
  • The buttermilk marinade keeps the chicken so tender you'll wonder why you ever skipped that step before.
  • Crispy onions add a shatteringly crunchy contrast that makes every bite feel like a celebration.
  • The garlic aioli ties everything together with a creamy tang that cuts through the richness perfectly.
  • Brioche buns turn this into something that feels indulgent without being fussy or complicated.
02 -
  • Don't skip marinating the chicken for at least 30 minutes, or you'll miss out on the tenderness and flavor that makes this sandwich worth the effort.
  • Keep the oil temperature steady at 350°F, because too hot and the coating burns before the chicken cooks, too cool and it gets greasy instead of crispy.
  • Press the breading firmly onto the chicken after dredging, otherwise it can fall off in the oil and leave you with sad, naked thighs.
  • Fry the onions in small batches so they crisp evenly, and don't crowd the pan or they'll steam instead of fry.
03 -
  • Use a thermometer to keep the oil at 350°F, it's the difference between perfectly crispy chicken and greasy disappointment.
  • Let the fried chicken rest on a wire rack instead of paper towels so the bottom stays crispy instead of steaming.
  • Make extra crispy onions because they disappear fast, and having extra means you can pile them high on every sandwich.
  • Toast the buns even if you think you don't have time, that buttery crunch makes the whole sandwich feel more complete.
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