In a large bowl, combine flour, garlic powder, onion powder, paprika, salt, black pepper, and cayenne pepper. Mix well.
In another bowl, whisk together eggs and milk until fully combined.
Dip each chicken thigh into the egg mixture, then coat with the flour mixture, pressing gently to adhere.
In a large skillet, heat about 1 inch of vegetable oil over medium heat until hot (about 350°F).
Fry the chicken thighs in batches for about 5-7 minutes per side, or until golden brown and cooked through. Remove and drain on paper towels.
In a small saucepan, combine honey, melted butter, and vanilla extract over low heat. Stir until well combined and warmed through.
Drizzle the honey butter mixture over the fried chicken thighs before serving.
Serve immediately with your choice of sides.