Sheet Pan Lasagna

Steps

1. Chop the red onion.
2. Chop one garlic clove.
3. Sauté the spinach in olive oil until wilted, then place it into a strainer and press out excess moisture.
4. In a skillet with more olive oil, cook the Italian sausage (removed from casing) until browned. Crumble as it cooks.
5. While the sausage cooks, take lasagna sheets and break them into 2-inch pieces (about four to five per sheet).
6. Add the browned sausage and chopped onion to a pot. Cook until the onion is soft.
7. Stir in marinara sauce and let it simmer on low while preparing other components.
8. Bring water to a boil, add salt, and cook lasagna sheets for about 4 minutes (until al dente).
9. In a bowl, mix ricotta cheese with the spinach mixture and a little salt.
10. Before draining the pasta, reserve about half a cup of the pasta water and add it to the sauce in the pot.
11. To assemble: Take a sheet pan (about 15x8 inches) and spread the entire contents of the sauce/pasta mixture onto the bottom. No layering is necessary.
12. Dollop the ricotta mixture all over the top of the pasta layer.
13. Sprinkle with half a cup of mozzarella and half a cup of grated Parmesan cheese.
14. Preheat oven to 425°F (or lower if needed after 20 minutes).
15. Bake for about 30 minutes, or until the top is crispy and cheesy. If it needs more time, reduce the oven temperature to 400°F.
16. Let the lasagna sit for 5-10 minutes before serving.