Sauté the minced garlic, and red pepper flakes in a tablespoon of olive oil for a minute, until the garlic is just golden. Add in the spinach with ½ teaspoon of salt and stir until it's wilted. Move the spinach to a strainer to drain any extra liquid, then mix it with the ricotta in a bowl.

Wipe down the skillet with a paper towel. Add the remaining olive oil and ground beef. Cook until browned and crumbled. Stir in the diced onion, Italian seasoning, and the rest of the salt. Cook until the onions are soft.

While the beef is browning, bring a large pot of salted water to a rolling boil and cook your lasagna pieces until they're al dente (follow instructions on the pasta package). Stir occasionally to prevent sticking. Drain, reserving 1 ½ cups of the pasta water.

Mix the marinara sauce with the beef & onion mixture. Add the reserved pasta water, the broken lasagna noodles, and half of both cheeses. Stir.

Pour the saucy pasta mixture onto your oiled baking sheet. Dot it with spoonfuls of the spinach-ricotta mixture and sprinkle the remaining cheeses over top.

Bake the sheet pan in the oven for about 30 minutes until the sauce is bubbly and the cheese browned.

Let the lasagna rest for 5 minutes and serve. Enjoy!