Bake Pie cooks uncooked pies in the player's inventory automatically, one by one, without the risk of burning them. However, in order to cook the pies, the player must have the minimum Cooking level required for the spell to actually work on the pie (boosts may be used). The usual Cooking experience is awarded for each pie baked with this spell. The quest Lunar Diplomacy must be completed to cast this spell.
Once cast, Bake Pie will automatically cook each pie in the inventory. However, one set of runes (or one astral rune if a steam battlestaff or equivalent is used) is required for each pie.