Heat Olive Oil in large, heavy duty sauce pan. Saute diced onions and garlic over medium heat for 3 minutes. Sprinkle generously with salt. Add San Marzano tomatoes. *Blend them in a food processor first if you want a saucier sauce. Add them straight from the can and smash them with a wooden spoon as they cook for a chunkier sauce).
Heat sauce over medium heat and reduce to med/low for simmering.
In a separate saute pan over medium, cook italian sausage until brown, about 8 minutes or so. Add to saucepan.
Add sugar, italian seasoning, oregano, and red pepper. Mix well. Add pepperoni and sopressata. Simmer for about 45 minutes.
After about 45 minutes, taste the sauce to make sure the flavor is how you like it and adjust accordingly. (don't forget about salt!) Add sliced mushrooms and olives if you are using them. Simmer for another 15 minutes.
While your sauce is cooking, boil water for pasta. Cook penne according to package directions. Don't forget to salt the pasta water! The water should taste like sea water.
When pasta is cooked, add pasta to the sauce and mix well.
In a large baking pan (at least 13x9, the deeper the better), put down a later of pasta. Cover with cheese. Alternate pasta and cheese layers until full. Finish the top with a layer of cheese.
Cover with foil and bake at 350°F for 30 minutes.
Remove from over and let sit for about 10 minutes to rest. Serve and enjoy!
Try some extra red pepper and fresh grate parmesan cheese on top!