Combine buttermilk and all spices in a bowl. Add chicken thighs, coat thoroughly, and marinate at room temperature for 20 minutes or overnight in the fridge.
Whisk waffle dry ingredients in one bowl. In a second bowl, whisk egg yolks, buttermilk, melted butter, and vanilla. In a third bowl, beat egg whites to stiff peaks. Mix wet into dry until just combined (lumps are fine), then gently fold in the egg whites.
Heat oil to 350°F in a heavy skillet. Mix flour, cornstarch, and baking powder in a shallow dish. Pull each thigh from the buttermilk and dredge twice through the flour mixture. Fry for 4–5 minutes per side until golden and cooked through. Drain on a wire rack.
Preheat your waffle iron. Pour in batter and cook until steam stops escaping, about 4–5 minutes per waffle. Keep finished waffles warm in a 200°F oven on a wire rack.
Combine honey, butter, hot sauce, cayenne, red pepper flakes, and salt in a small saucepan over low heat. Stir until butter melts and sauce is smooth. Do not boil.
Place waffle on the plate, top with fried chicken, and drizzle generously with hot honey sauce. Finish with flaky salt or fresh thyme if desired.