Lasagna, whether it has a meat or vegetable filling, is often served with a side of green salad or, in Italy, with a single vegetable, such as leeks in Tuscany. In keeping with the dish's Italian origins, recipes for vegetable lasagna tend to call for a mix of produce used in Mediterranean cuisine, such as courgette, butternut squash, artichoke, eggplant and spinach.
Lasagna can be made with a single vegetable, as is the case with roasted butternut squash lasagna, combined with cheese, butter, amaretti cookies and nutmeg. Alternatively, lasagna can be made with numerous different varieties of the same vegetable, such as mushroom or fungi.
For a meat lasagna with a Bolognese sauce, some basic vegetables to add to the mix include onions, garlic, carrots, celery and tomatoes.
For vegetable lasagnas, the Bolognese sauce can be adapted as a tomato Ragu with pureed eggplant. When selecting a cheese sauce to use, consideration should be given to the vegetable flavors, which tend to be subtle by comparison with meat. A light ricotta, for instance, might be a more sensible choice than a heavy bechamel. That said, vegetable flavors can be concentrated and strengthened by roasting them in olive oil before adding them to the lasagna.