Lasagna Recipe without bratwurst

1½ cups marinara sauce 1½ cups mozzarella cheese, shredded (or 1 cup of cheese and ½ cup of Béchamel sauce) ½ lb. sausage , ground (or beef) 6 lasagne noodles[...]

2 Tbsp olive oil 1 Cup chopped yellow onion (1 onion ) 2 garlic cloves minced 1 1/2 pounds Italian turkey sausage casings removed 1 28-oz can crushed tomatoes[...]