If needed, parboil/cook the lasagna sheets and then lay out in a single layer on cooling racks to keep from sticking and tearing.
While those are cooking, chop and sauté the onion and garlic in a large nonstick plan with the olive oil. Cook until the onions are translucent and then add in the ground meet. Cook through and then add in all of the tomato sauce.
Work in layers starting with the meat sauce on the bottom of the oven safe baking pan. Then add on the lasagna sheets, and a thin layer of the ricotta, sprinkle with a decent amount of the nutritional yeast. Then place a layer of the thin sliced beets on.
Repeat these steps in this order until you have used all of the ingredients, ending with sauce and a sprinkle of the nutritional yeast.
Cover and cook at 375 for about 35 to 40 minutes or until the noodles puff up and the top of the lasagna is uneven and puffy. Allow to cool for a few minutes before slicing and serving.