Place bacon in a large, deep skillet. Cook over medium high heat until evenly browned. Drain, crumble, and set aside. Preheat oven to 325F. Melt butter in the microwave, or in a small pan on the stove over low heat. Spray a 9x12-baking dish with vegetable spray. Place croutons in the bottom of the dish, and drizzle with melted butter. Sprinkle with grated cheddar cheese. Crack the eggs into a bowl, whisking to break up the yolks. Add milk, peppers, mustard, salt, and pepper, and beat until well combined. Pour over the croutons and cheese, and sprinkle with crumbled bacon. Bake in the preheated oven for 40 minutes. Remove form oven and allow to stand 10 minutes before serving.