Red Pepper, Mozzarella, and Pepperoni-Stuffed Chicken

Preheat the oven to 350 degrees F. Meanwhile, place chicken breasts skin side up on clean work surface and rub all sides with cut garlic clove. Starting about 1/3 inch beneath skin and using sharp knife, carefully make slice parallel to skin down length of the breast, without cutting all the way through breast (the flap should open a book). Season all sides (including the interior) of breast with salt and pepper. In large stainless steel or cast iron skillet, add 1 tbsp. olive oil over medium-high heat. When oil is hot but not yet smoking, add chicken breasts skin side down, leaving as much space between them as possible (work in batches of two if needed to keep pan from crowding). Cook until skin is golden brown and releases easily when moved, 4 to 5 minutes. Flip and repeat on remaining side. Turn off heat and let cool for few minutes. Once cool enough to handle, stuff cavities of each chicken breast with 2 to 3 tbsp. mozzarella. Place several pepper strips and 2 to 3 slices pepperoni atop cheese (it’s okay if edges are dangling out a little). Transfer to oven and cook until chicken is just about cooked through and cheese is melted, about 8 minutes. Turn up heat to 450 degrees F and cook 5 minutes more to help crisp pepperoni and chicken skin.