In a mixing bowl, combine ground turkey, cumin, chili powder, garlic powder, onion powder, cayenne pepper, beaten egg, bread crumbs, salt, and black pepper. Mix until just combined.

Form the mixture into 4 equal patties, making a slight indentation in the center of each to prevent puffing during cooking.

Preheat the grill to medium-high heat. Place the patties on the grill and cook for about 5-7 minutes on each side, or until the internal temperature reaches 165°F (74°C).

During the last minute of cooking, place a slice of pepper jack cheese on each patty and close the grill lid to melt the cheese.

Spread chipotle mayo on the bottom half of each toasted bun.

Add the cooked turkey patty with melted cheese, followed by lettuce, tomato, and jalapeños if using. Top with the other half of the bun.