Put your combo cooker or Dutch oven on the oven rack, and preheat the oven to 450°F (232°C) for at least 30 minutes.
Place an oven rack in the bottom third of the oven with no rack above it. Put your combo cooker or Dutch oven on the oven rack, and preheat the oven to 450°F (232°C) for at least 30 minutes. If you’re using a combo cooker, place the shallow side face up on one side and the heavier, deep side face down on the other.