Instructions. 1  Preheat the oven to 400°F: Turn on the oven and preheat to 400°F. Place a rack in the lower third of the oven. 2  If you're cooking multiple sheets of bacon, position a second rack in the top third of the oven. 3  Arrange the bacon on a baking sheet: Line a baking sheet with foil (this makes clean-up easier).