Heat a large nonstick skillet over medium-high heat; coat pan with cooking spray. Add bell pepper mix; cook 5 minutes, stirring frequently. Add garlic; cook 1 additional minute.
While bell pepper mixture cooks, arrange half of potato slices in bottom of an 11 x 7-inch baking dish coated with cooking spray. Combine salt and pepper. Sprinkle potato slices with half of salt mixture.
Layer potato mixture with half of bell pepper mixture and one-third of cheese. Repeat procedure with remaining half of potato slices, salt mixture, bell pepper mixture, and remaining two-thirds of cheese.
Cover and bake at 400° for 40 minutes. Uncover and bake 10 additional minutes or until cheese is lightly browned and potatoes are tender. Sprinkle with cilantro.