Meanwhile, in a small sauce pan, steam the sweet potato chunks until tender, about 10 minutes. Remove from heat and mash well. In a food processor, combine the sweet potatoes, almond or soy milk, nutritional yeast, salt, lemon juice, soy sauce, yellow mustard, garlic powder, and chili powder. Taste and add a little more yeast or salt if needed.

In a large bowl combine the pasta, broccoli and sauce and stir well to combine. Pour into a large casserole dish and scatter breadcrumbs evenly across the top. Bake in the oven until sauce is bubbly and the breadcrumbs are slightly crisp, about 20 minutes.