Vegetable lasagna is a great alternative to a more traditional meat lasagna. It can appeal to everyone, not just vegetarians, and is a relatively simple dish to make. Vegetable lasagna also freezes very well, so it can be made ahead and eaten later.
Lasagna is generally made with three or four layers of lasagna noodles, a cheese mixture, and sauce which may or may not include ground meat. You may choose to use flat or ridged lasagna noodles. Flat noodles are more traditional, but some feel that ridged noodles catch more of the sauce. The cheese mixture is usually made up of ricotta, mozzarella, and sometimes Parmesan or Romano. A vegetable lasagna can simply be a traditional lasagna that includes vegetables instead of meat in the tomato-based sauce, or it can be made with an Alfredo-style sauce.
Some of the veggies you may choose to use in vegetable lasagna include mushrooms, onion, zucchini, squash, broccoli, spinach, artichokes, tomato, eggplant, pepper and garlic. There are no set rules, though, and you can use any vegetables that you like or have left over in the fridge. Vegetable lasagnas can be a healthier alternative than traditional lasagnas, with some simple substitutions.
Obviously, substituting vegetables for meat will make the dish healthier. However, you could also choose to use whole wheat lasagna noodles, which are higher in fiber than traditional pasta made with white flour. If you choose to use a white cheese sauce instead of a traditional tomato sauce, preparing your own and using low-fat milk or cream will make the dish lower in fat. Choosing part-skim or fat-free cheeses for the cheese mixture will also lower the fat content while keeping the protein content high. It is also possible to use noodles that do not need to be pre-boiled -- they will soften and bake in the oven, absorbing the moisture from the sauce and vegetables.
There are a number of vegetable lasagna recipes to be found in cookbooks and online, but you could easily invent a recipe yourself as well. Some general instructions for making vegetable lasagna are to spray the lasagna dish with cooking spray to prevent sticking, then place a layer of noodles, a layer of sauce and vegetables, and a layer of cheese. You will repeat these steps three or four times depending on the size of the lasagna you are making. Lasagnas generally take between 50 minutes and an hour and a half to bake, depending if you are using no-boil noodles or are cooking a previously frozen lasagna. It is a good idea to cover the lasagna with tin foil for most of the baking time, then remove the tin foil for the last ten to 15 minutes so the cheese on top can melt.