Saute onions in a large pot with about 2 tablespoons of olive oil. When onions have become translucent, add the two jars of marina sauce and can of chopped tomatoes. Turn down to simmer.
In a large skillet, brown ground beef and Italian sausage until completely cooked, drain fat from meat, and add meat into the large pot with the sauce. Add chopped pepperoni to the sauce mixture. Add 1 teaspoon of Italian seasonings to mixture and allow all to simmer for about 20 minutes before you season to taste with salt and pepper.