Prepare the cauliflower Alfredo according to directions if you haven’t already (you’ll need to roast or steam the cauliflower before making it
Preheat the oven to 375F.
In a medium bowl, toss the lentils with the vegan pesto or chopped basil and set aside.
Slice the sweet potatoes into thin rounds, using a very sharp knife and a cutting board. Then slice the tomato into thin rounds as well, and set aside.
Assemble the lasagna in a large baking dish for casseroles. Place enough sweet potato rounds to cover the bottom of the dish. Then spoon heirloom tomato slices, topped with spinach, 1 cup basil lentils, and cauliflower Alfredo.
Repeat until you’ve filled the casserole dish or run out of ingredients, finishing with the cauliflower Alfredo on top.
Cover the vegan lasagna and bake for 45-55 minutes, or until the sweet potatoes are soft when poked with a toothpick. To brown the cauliflower sauce on top, remove the cover and let cook for 5 extra minutes in the oven.
Remove from the oven and let cool for 10 minutes before serving.