Heat Exposure

• Most pastries such as cakes, pies, cookies, muffins and breads are baked uncovered to allow the dough or batter to absorb heat from all angles, to release steam and to rise properly. Once an oven reaches the proper baking temperature for a particular item, the entire oven registers the same temperature if it is operating properly. This is why it's important to keep a thermometer in the oven at all times, as it alerts you to any discrepancies between temperature settings and actual oven temperature.

Heat Sensitivity

• Casseroles such as baked lasagna and desserts such as bread pudding generally require a longer baking time than cakes and other pastries, which lengthens their exposure to heat. Therefore, they are often covered to retain steam produced during baking and to keep their tops from burning. In some instances, the covering, which can be the lid designed to fit the pan or aluminum foil, is removed part-way during baking to allow the top to brown slightly.

Meats, Etc.

• The act of baking meats is more generally called roasting, and most meats are left uncovered to maximize heat absorption and create a crispy outer crust. In some cases, however, such as when roasting a very large turkey at low heat for an extended time, covering parts of the bird with aluminum foil keeps them from drying out or turning too crispy. The same holds true for meatloaves, to assure that they bake thoroughly without drying out the top and sides. In both cases, removing the foil during the last few minutes of roasting produces a crispy finish once the meat's internal temperature has reached a safe level, which is at least 165 degrees Fahrenheit for both baked meatloaf and roast turkey.

Consider This

• Recipes involving uncooked pasta or rice are generally covered and often uncovered to finish baking, while partially cooked pasta or rice casseroles are not covered. The general rule is that, unless a recipe specifically calls for covering a dish during baking, leave it uncovered. If you notice the food is cooking quickly and the top is browning before the baking time is up, cover it lightly with foil to keep it from scorching.