All ingredients ready? Let's begin!
If you’re going to bake the lasagna immediately, start by preheating your oven to 350⁰F (180⁰C).
Grease or spray a deep casserole dish with non-stick spray.
Make the sweet potato cheese sauce by folding the sweet potato puree, ricotta cheese, and cottage cheese with a spatula. Set aside.
Move on to the tomato sauce. Finely dice the onion, mince the garlic, and roughly chop the spinach.
Heat your olive oil in a heavy frying pan. Add the onion and cook for 5 minutes.
Add your chopped spinach and minced garlic to the pan and cook for another 2 minutes.
Pour in the marinara sauce. Heat to a simmer. Simmer for 2-3 minutes.
Assemble your lasagna by layering ½ cup tomato sauce, cover with lasagna sheets, and adding ½ cup cheese sauce.
You may have to break the lasagna sheets to fit your casserole dish.
Repeat the layers until you have used all the sauce.
Bake for 25 minutes. Remove the sweet potato lasagna from the oven and top with mozzarella cheese.
Put the thoroughly cheesy lasagna back in the oven for another 10 minutes until the cheese has melted and turned golden brown and bubbly.
Allow the lasagna to stand for 10-30 minutes before serving so that the layers can set and not slide apart as you cut into them.
Garnish with freshly chopped basil before serving.