<human>:  How to make vegan lasagna?
<bot>: Start by preheating your oven to 350 degrees Fahrenheit. Then, prepare your lasagna noodles according to the directions on the package. For the sauce, combine a can of diced tomatoes, tomato sauce, garlic, oregano, basil, and a tablespoon of sugar in a saucepan and simmer for 10 minutes. For the filling, sauté onions, bell peppers, and mushrooms in olive oil. Once cooked, add vegan crumbles or cubed tofu, then stir in your tomato sauce and simmer for another 10 minutes. To assemble your lasagna, spread a layer of the tomato sauce over the bottom of a greased baking dish, then layer lasagna noodles, the fillings, and your remaining sauce. Top off with a covering of vegan cheese. Bake for 35-40 minutes, or until your vegan lasagna is golden and bubbly. Enjoy!