Brown meat, onion, and green pepper (and mushrooms if desired), adding garlic salt. Drain fat.
Add tomato sauce and bring to a simmer, cover and cook for at least 1 hour.
Meanwhile, cook the lasagna noodles in salted water (reserve the cooking liquid) until barely al dente (about 7 minutes) and combine the cottage cheese and mayonnaise in a bowl.
Preheat oven to 350°F.
Grease a 13X9 pan with butter. Evaluate the sauce, if it has cooked for a long time and lost a lot of liquid, thin it by adding 1/4 cup at a time of cooking liquid from the noodles. Add as much as desired to get the right consistency: thick but spreadable. This will also make your sauce "sticky" so it will coat the noodles.
Spoon a thin layer of sauce into the bottom of the dish. Layer noodles (overlapping if necessary), 1/2 meat mixture and 1/2 the cheese mixture.
Cover with the rest of noodles, meat and cheese mixture. Top with shredded mozzarella.
You can store this in the refrigerator or freezer at this point until ready to heat. Allow extra time for reheating from cold or frozen state. Spray a sheet of foil with cooking spray and cover the lasagna with it. Bake for 1 hour.
Uncover and continue baking until the cheese is bubbly and browning.