According to Eunice Feller, master baker/chef of Bread and Chocolate, there are no hard and fast rules, but these are her guidelines: no grease: - baking a lean bread or pizza, directly on a baking stone - cookies, tea breads and cakes in pans lined with parchment paper - angel food cake - using silicone pans - well seasoned cast iron pans everywhere else, use a baking spray/butter/oil. if in doubt, use a baking spray/butter/oil. you've put in the time, and good ingredients to get your batter and/or dough perfect, it would be a shame if you can't get the baked goods out of your pan.