Preheat oven to 375º.
Chop the onion into bite-sized pieces until you have ½ cup.
Brown the ground beef and onion together in a large sauce pan on high heat until the meat is browned.
Drain the excess fat from the meat mixture.
Add in the next 5 ingredients: oregano, salt, pepper, ketchup and minestrone soup.
Simmer on medium heat for 5 minutes.
Cover the bottom of the 9 x 13 casserole dish with the crescent rolls.
Spoon the meat filling over the rolls.
Sprinkle cheese over the top.
Bake at 375º for 15-20 minutes. Serve warm!