Prep the chicken. Trim excess fat and cut thighs (or breasts) into slider-size pieces, about 2 to 2.5 inches wide.
Aim for uniform thickness so they fry evenly.
Make the marinade. Whisk buttermilk, egg, hot sauce, and salt. Add chicken and toss to coat. Cover and chill at least 1 hour, up to overnight for extra tenderness.
Mix the dredge. In a large bowl, combine flour, cornstarch, salt, black pepper, paprika, garlic powder, onion powder, and cayenne.
Taste a pinch to check seasoning before coating the chicken.
Set up your station. Place the dredge next to the marinade. Line a tray with a wire rack for the coated pieces. This helps them set and stay crisp.
Coat the chicken. Remove a piece from the marinade, let excess drip off, then press firmly into the seasoned flour.
For extra craggy crunch, dip back into the buttermilk and again into the flour. Place on the rack and let sit 10 minutes.
Heat the oil. In a heavy pot or deep skillet, heat 1.5 inches of oil to 350°F. Use a thermometer for accuracy.
Keep a sheet pan with a rack ready for draining.
Fry in batches. Add a few pieces without crowding. Fry 3–5 minutes per side, until deep golden and the thickest part hits 165°F. Adjust heat to keep oil between 325–350°F.
Drain and season. Transfer fried chicken to the rack, then sprinkle a light pinch of salt while hot.
This wakes up the flavor.
Toast the buns. Split slider buns and toast cut-side down in a dry skillet with a touch of butter until lightly golden. This keeps them from getting soggy.
Make the sauce. Stir together mayo, mustard, pickle or lemon juice, hot sauce or smoked paprika, sugar, salt, and pepper. Adjust to taste—more tang, more heat, your call.
Assemble. Spread sauce on both sides of the buns.
Add lettuce or slaw, a piece of fried chicken, pickles, and any extras. Top and press gently.
Serve right away. Sliders are best while the chicken is hot and crisp. Add hot honey if you want sweet heat.