A roasting pan is generally used to roast items on the stove or oven, such as turkey, vegetables, potatoes or chicken. Roasting pans can be a heavy tin foil and disposable or can be sturdy cooking pans found at department and speciality stores, designed for multiple uses. The main purpose of a roasting pan is that it can hold up under high heat. While roasting items is the pan's primary purpose, roasting pans can also be used in other recipes, including cooking lasagne.
Preheat the oven to 149 degrees Celsius. Wait until the oven has fully heated before placing the lasagne in the oven to ensure it cooks properly.
Place a roasting pan on the counter. Grease the bottom of the pan thoroughly with a cooking spray or other form of grease, making sure to get all four sides and all the corners of the pan. Sprinkle a light layer of Parmesan cheese along the bottom and sides of the pan.
Fill with a lasagne, using a recipe of your choice.
Stop layering the noodles, sauce and cheese after the second layer. Measure the thickness of the lasagne by standing a ruler either inside the pan or next to the roasting pan. Do not add any more layers if the thickness of the lasagne is more than four inches because it will not cook evenly.
Place a lid on the roasting pan or cover the pan tightly with tin foil. If using foil, pinch the sides of the foil over the sides of the roasting pan, so a tight seal is formed. Place the pan in the oven, and bake the lasagne.
Check the lasagne every hour to see how it is baking. Add four to five tablespoons of tomato sauce if the lasagne appears to be drying out. Place a cooking thermometer in the middle of the lasagne to check the temperature in the centre. Wait until the temperature is at least 73.9 degrees Celsius, which takes between three and four hours.
Check the lasagne after about 30 minutes to see how it is baking. Place the roasting pan in the refrigerator, if not baking right away.
Do not use oil to grease the pan because it will not prevent the noodles from sticking to the roasting pan. Be aware of the thickness of the lasagne, if it is more than four inches thick, the sides will cook faster than what is in the centre of the pan .