Preheat oven to 400.
Slice sweet potatoes thin length-wise. Dice the onion and mince the garlic.
Heat a large skillet over medium heat. Add olive oil, and sauté diced onion for about 5 minutes until beginning to soften. Add garlic, stir and cook for 1 minute. Add ground beef. Stir and cook until no longer pink.
While beef cooks, whisk the egg with the cottage cheese. When the beef is cooked, add jar of spaghetti sauce, Italian seasoning, salt and pepper. Stir to combine.
To assemble lasagna, start with a layer of sweet potato covering the bottom of a 9x13 pan. Add half of the meat sauce, spread to cover sweet potatoes. Then add half of the cottage cheese/egg mixture, spread so it is an even layer. Add a third of the mozzarella, then repeat that same order one more time.
After your second layer of cheese, add the spinach, and finish off with a final sprinkle of mozzarella cheese. Bake uncovered for 45 minutes. Then, turn off the oven, and leave the lasagna in the oven for 15-20 minutes while the oven cools down. Do not skip this step, your sweet potatoes will not be soft after the initial 45 minutes bake-time. Enjoy!
