Place the 2 whole boneless skinless chicken breasts onto a large wooden cutting board. Pat them completely dry with a paper towel. Drizzle 1 tablespoon of olive oil evenly over both sides of the meat. Sprinkle 1 teaspoon of coarse sea salt, 1/2 teaspoon of cracked black pepper, and 1 teaspoon of garlic powder across the surfaces. Rub the spices into the meat using your hands to ensure full coverage. You want the seasoning to form a tight uniform layer over the pale-pink chicken. (I tried skipping the paper towel step once and the spices just clumped up instead of sticking properly.) Make sure the surface is coated well before cooking. The dry surface allows the oil and spices to adhere tightly to the skinless meat. This step builds the savory crust during searing.

Place a 10-inch cast-iron grill pan over medium-high heat until the surface is hot but not smoking. Lay the 2 seasoned chicken breasts down carefully onto the hot ridges. Cook them without moving for exactly 6 minutes on the first side. Flip the chicken pieces over using tongs to reveal deep dark-brown char marks on the cooked side. Cook for another 5 to 6 minutes on the second side. You'll hear a loud sizzling sound as the fat renders and the crust caramelizes. The meat is ready when it reaches an internal temperature of 165°F. Miss this window by going too long and the breast meat becomes chalky and dry. Cook hot and fast on the heavy ridges. The intense heat locks in the moisture while creating deep smoky lines. This builds flavor without drying out the center.

Transfer the 2 cooked chicken breasts back to the wooden cutting board. Let the meat rest for 5 minutes off the heat before touching it. Slice each breast lengthwise into thin strips then cut across to create half-inch cubes. You will see steam rise as you cut through the deep amber crust. The interior should look completely white and opaque but glistening with juices. Skip the rest and the juices run out the moment you cut. That leaves the meat dry inside the wrap. Rest 5 minutes before slicing. This gives the internal juices time to redistribute throughout the meat fibers. It guarantees every single bite stays tender.

Lay 4 large flour tortillas flat on a clean workspace. Spread 1 tablespoon of creamy mayonnaise across the center of each tortilla. Divide 2 cups of shredded romaine lettuce and 1 cup of diced roma tomatoes evenly among the wraps. Scatter the diced grilled chicken pieces over the vegetables in an irregular pile. Top each with 1 cup of shredded sharp cheddar cheese. The ingredients should form a colorful layered strip down the middle of the soft beige dough. (I tried using wet tomatoes once and it made the bottom soggy so drain them well first.) Layer the cool vegetables beneath the warm chicken. The residual heat from the meat starts to soften the sharp cheddar slightly. This creates a cohesive filling before folding.

Fold the left and right sides of each tortilla inward over the filling. Roll the bottom edge up tightly over the sides and continue rolling until you form a neat bundle. Place the 4 assembled wraps seam-side down back into the hot 10-inch cast-iron grill pan. Press down gently with a flat spatula for 2 minutes over medium heat. Flip each wrap carefully and toast the top side for another 2 minutes. You'll watch the pale tortilla turn a beautiful golden-brown with dark parallel char marks. The sharp cheddar inside will melt completely into the warm chicken. Go past 3 minutes per side and the outer wrap scorches. Grill seam-side down first. The heat seals the overlapping dough edges together instantly. This prevents the wrap from opening up while eating.