1 to 2 baking sheets
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. If you're cooking multiple sheets of bacon, position a second rack in the top third of the oven.
Arrange the bacon on a baking sheet: Line a baking sheet with foil (this makes clean-up easier). Lay the bacon on the baking sheet in a single layer. The bacon can be close together, but don't let it overlap or the bacon will stick during cooking. If necessary, use a second baking sheet.
Bake the bacon: Place the baking sheet of bacon in the oven and bake until the bacon is deep golden-brown and crispy, 15 to 20 minutes. Exact baking time will depend on the thickness of the bacon and how crispy you like it. Begin checking around 12 minutes to monitor how quickly the bacon is cooking. The bacon fat will sputter and bubble as the bacon cooks, but shouldn't splatter the way it does on the stove top. Pour off the bacon grease as needed so the bacon isn't totally submerged in grease.
Cool the bacon: Remove the bacon from the oven and use tongs to transfer it to a paper-lined platter to drain and finish crisping. Serve immediately. You can also refrigerate leftover bacon for a week or freeze it for up to three months; warm the bacon in the microwave before serving.
Clean up: If you want to save the bacon grease, let it cool slightly, then pour it into a container and refrigerate. If you don't want to save the grease, let it solidify on the baking sheet, then crumple the foil around it and discard.
Even Crispier Bacon: For even crispier bacon, set a metal cooling rack over the foil-lined baking sheet and lay the raw bacon over the cooling rack. Elevating the bacon allows it to cook from all sides and become extra-crispy.