Clean and cut zucchini and eggplant into thin lengthwise slices. Easier with a Mandolin, but not necessary. Place the sliced eggplant onto paper towels and lightly sprinkle with salt, let sit for 15 minutes and then blot dry, this will help release some of the liquid.
Place cannellini beans, basil, garlic, nutritional yeast, onion, and salt in food processor. Process until it becomes a smooth consistency.
In large rectangular baking dish start putting the lasagna together. Start with a cup of red sauce and layer the ingredients. First zucchini slices then eggplant, cannellini mixture, spinach and then sauce (not too much). Repeat process until the last layer is zucchini. Should be about three layers depending on how big or small your vegetables are.
Top last layer with remaining sauce and sprinkle with nutritional yeast. If you have some cannellini mixture left, spread a thin layer onto the top of the last layer. Cook uncovered in the oven for 45-50 minutes. Broil for 5 minutes until lightly browned.
Notes
If you aren't a fan of one of these veggies, you can use any squash sliced thinly as a noodle replacement.