Preheat oven to 350 degrees. Spray casserole dish with a non-stick spray and place sourdough bread on the bottom of casserole dish. Beat eggs; add salt, pepper and evaporated milk and mix thoroughly. Pour egg mixture over bread. Sprinkle diced ham and shredded cheese over egg mixture and cover with plastic wrap or another type of lid. Place casserole in the refrigerator overnight or in refrigerator for at least five hours.Bake for 20 to 22 minutes, depending on the depth of the casserole dish. You will know this is completely done when you shake the dish slightly and the eggs do not wiggle.