Grilled Pesto Chicken Sandwiches

Deselect All

2 large boneless skinless chicken breasts (about 12 ounces each)

1/2 teaspoon crushed red pepper flakes

1/2 teaspoon fennel seed, lightly crushed with a knife

2 tablespoons olive oil

Kosher salt

4 soft hoagie rolls, split

Four 1/4-inch-thick slices mozzarella

1 large tomato, sliced

1/2 cup prepared pesto