Preheat the oven to 375F
Start thawing your spinache according to the package directions. You don't need it hot, just warm enough to squeeze out the excess water.
In a large pot over medium high heat, brown and crumble the sausage and ground beef with the onion and garlic, drain any excess grease. Season with salt and pepper, and garlic powder. Stir in the marinara and turn to medium low. Let simmer while you mix the cheese sauce.
In a separate medium mixing bowl, mix together the ricotta, eggs, Italian seasoning, garlic, and 1 cup of the parmesan cheese.
In a large 9x13 casserole or baking dish, layer half of the meat mixture in the bottom.
Pour your cheese sauce out evenly over the meat sauce layer you just put down and gently smooth it out.
Squeeze as much water as you can from your chopped spinach, and spread it out evenly over the cheese sauce.
Now the rest of the meat mixture goes on top, and gets smoothed out
Finish off by sprinkling the mozzarella and parmesan on top.
Bake in the pre-heated oven for 30 minutes. Remove from oven and let rest for 10 minutes before serving.