Make the homemade buttermilk biscuits (click here for easy recipe)
MAKE THE SRIRACHA MAYO:
Mix all ingredients in a small bowl, cover with plastic wrap, and keep in the fridge until ready to use (can be made a day before).
MAKE THE CHICKEN AND ASSEMBLE:
Lightly season the chicken thighs with salt and pepper.
Whisk flour, 1/2 teaspoon pepper, 1/2 teaspoon salt and the garlic powder in a medium bowl.
Pour buttermilk into another bowl, and add hot sauce (to taste, 3 - 5 shakes is good).
One piece at a time, dredge the chicken in the flour mixture, and shake off the excess.
Dip in buttermilk, allowing excess to drip back into bowl, and then dredge again in the flour mixture, shaking off excess. Continue with remaining chicken. Place in fridge.
Pour oil into a large heavy skillet to a depth of 1/2-inch.
Add deep-fry thermometer in oil and heat to 350 F. (or toss in a small piece of bread, should sizzle and start to brown after a minute or so).
Take chicken out of fridge and fry in batches until golden brown and cooked through, about 3 minutes per side.
Transfer to a wire rack.
Smear some sirarcha mayo on each side of the cut buttermilk biscuits.
Top with a couple pieces of the fried chicken.
Add a couple bread-and-butter pickles (optional).
Top with biscuit top.