Combine all dried spices in a small bowl: smoked paprika, Italian seasoning, dried thyme, chili flakes, cayenne pepper, onion powder, garlic powder, garlic salt, and freshly ground black pepper. Mix thoroughly to ensure even distribution of spices. This dry blend is the foundation of the blackening crust, so make sure everything is well combined before coating the chicken.

Pound the chicken breasts to an even 1/2-inch thickness using a meat mallet—this ensures they cook evenly without drying out. Generously coat both sides of the chicken with the spice blend from Step 1, pressing the spices gently into the meat so they adhere well. I like to season the chicken right before cooking so the spices don't sit too long and lose their potency.

While the grill heats, melt the unsalted butter in a small saucepan over low heat and stir in the fresh minced garlic. Let it warm gently for 1-2 minutes until fragrant, being careful not to brown the garlic. Set aside and keep warm—this will be brushed onto the finished chicken for extra flavor.

Heat your grill to 400°F. Once hot, place the seasoned chicken breasts directly on the grill grates. Grill for 4-5 minutes on the first side without moving them—this allows the spices to form a flavorful blackened crust. Flip and grill the second side for another 4-5 minutes until the internal temperature reaches 165°F at the thickest part. I prefer to use a meat thermometer to check doneness rather than relying on time alone, since chicken thickness can vary slightly.

Transfer the grilled chicken to a serving plate and brush both sides generously with the garlic butter from Step 3. Serve immediately while hot, allowing the garlic butter to create a glossy finish and add extra richness to the blackened crust.