Preheat oven to 375 degrees.
Grind cashews in the food processor as finely as possible, then add tofu and blend until you get the consistency you like. Mine varies; sometimes i make it very creamy and other times more like cottage cheese. Blend a little and then pulse if you don't want it totally creamy.
Add lemon juice, salt, pepper, and any other seasoning you like, gradually to taste so as not to overdo it. The lemon juice should not be so much that it gives a lemony taste but should be enough to add a slight cheesy tang.
Toss veggies with seasoning to taste.
Line lasagna dish with parchment paper and build lasagna bottom up as follows: sauce, pasta, "ricotta," veggies; repeat until ingredients are gone. Make sure there's sauce leftover to cover the very top pasta layer before baking.
Fill your empty pasta jar to the top with water and pour around the edges of the lasagna.
Cover with foil and bake for about an hour (check at about 45 minutes).