If using cooked hamburger patties, cut into long slices and cut in half. Slice sausages if using. Add to a large skillet and fry to brown slightly.
If using ground beef and onions, add ground beef to the pan and let brown for 3-4 minutes without stirring. Add onions, and cook ground beef, breaking up, until cooked through and onions are softened. (Drain if necessary)
Add gravy, tomato and tomato paste. Bring to a boil, reduce heat to simmer.
Meanwhile, while ground beef is cooking, boil water for macaroni and cook macaroni noodles to al dente per time on the package.
When there are 5 minutes left for cooking the macaroni, add the frozen peas along with the pasta.
Once the macaroni and peas are cooked, drain and add to beef mixture in the skillet. Remove from heat, stir and let sit for 2 minutes.
Serve and sprinkle with parmesan cheese and pepper to taste.
Notes
The gravy and tomatoes add quite a bit of salt, so it's not recommended to add more. However, adjust to taste.
Use low sodium versions for ingredients to reduce sodium intake.
Use any preferred gravy flavor. Or substitute with leftover homemade gravy, or equivalent dry gravy mix with water.