Cooking Time

• Covering a lasagna with aluminum foil makes it cook faster because the foil keeps in heat and traps steam. Covering a lasagna also keeps the dish moister and prevents it from drying out or burning. Depending on the pan's size, most lasagnas cook in 30 to 40 minutes, or just until the top layer is golden brown and the lasagna is bubbly. Large frozen lasagnas can take an hour or more to cook.

Method

• To cover a lasagna with aluminum foil, secure the foil loosely over the edges of the pan or crease it in the middle so it makes a low tent. This method ensures that the cheese won't melt and stick to the foil. Take the foil off during the last five minutes of cooking time to allow the cheese to brown slightly. Watch it closely, however, so it browns but doesn't burn. If you're cooking a frozen lasagna, follow the package directions closely for best results. Don't use foil in the microwave oven. The foil deflects the microwaves, causing the food to cook unevenly. In some cases, using foil can even damage the oven.

Considerations

• You can purchase aluminum foil in various sizes and grades, from regular- to heavy-duty. For covering a lasagna, regular-weight foil suffices. After the lasagna has cooked, scrape off any cheese from the aluminum foil and spread it over the lasagna. Discard or recycle the foil and don't store leftovers in it. The acid in the tomato sauce can interact with the aluminum, causing tiny bits to leach into the food and create a metallic taste.

Substitutions

• If you don't have a sheet of aluminum foil, you can use the glass lid that sometimes comes with casserole dishes. Alternatively, make lasagna in a slow cooker. Layer lasagna noodles with meat sauce diluted with water, ricotta cheese and shredded mozzarella cheese. Cover and cook on low for four hours. Cooking lasagna in a slow cooker produces superior results. The lasagna is always moist and tender, without the fuss of boiling noodles or watching the oven.