For a "batch" of sauce:
1/2 yellow or white onion, diced
2 cloves garlic, diced
1 T olive or vegetable oil
1 28 oz can crushed tomatoes
1 T dried basil or 1/2 C fresh basil leaves
1 tsp dried oregano or 1/4 C fresh oregano leaves
1 tsp sugar
salt and pepper
Heat oil in saucepan over medium heat. Saute onion and garlic until soft seasoning with a little salt and pepper. Add can crushed tomatoes. Add basil, oregano, and sugar. Heat until bubbling slightly and then turn temp down to low. The sauce is ready at this point, but the longer it simmers the richer and darker it gets, so it's really a matter of personal preference.
For the lasagna I used a 18x12x5 pan. For the layers I used 3 batches of the sauce described above, 2 lbs ground turkey browned and seasoned with salt and pepper, 2 boxes of lasagna noodles, a pint of ricotta cheese, a large can of canned mushrooms, and 2 16 oz balls of fresh mozzarella cheese, shredded.
Start with a layer of sauce on the bottom (noodles will just burn to the bottom of the pan) then a layer of noodles, a layer of ground meat, then you can put sauce if you want or just another layer of noodles. Pretty much just layer anything you want between the alternating layers of sauce and noodles. I thought I'd put the more moist layers, such as the ricotta cheese and mushrooms, toward the top so the juices get distributed through the lasagna rather than having the lasagna cook in a pool of liquid at the bottom of the pan. I also put a layer of mozzarella cheese in the middle as well as at the top, and that worked out excellent because there was stringy, melted cheese along with bubbly, crispy cheese at the top.
Bake at 375 for about an hour then heat under the broiler for about 5-10 minutes or until the top layer of cheese is bubbling and golden brown. Let the lasagna rest for at least 10 minutes before slicing.