The recipe is a layered casserole with polenta, chopped peppers (red, orange, yellow), black beans, tomato sauce and cheese. Gilbert is a texture eater, so black beans (big on protein, low on fat) is not on his approved list. As an alternative, I used refried black beans instead. Looks like it worked!
In future versions, I might add some purees to the sauce such as eggplant, onions, and zucchini to give it more flavor and increase the veggie count. But for now, I'm happy with the outcome!