This dish is a winner in our house, I never have to worry about leftovers!

Servings: 6

12 oz spaghetti, cooked and drained
1 tablespoon olive oil
1/2 cup onion, chopped
2 garlic cloves, minced
1 pound ground beef
1 cup ranch dressing
1 cup sour cream
1 cup shredded cheddar cheese
1 cup mozzarella cheese, shredded
1/2 teaspoon salt
1/2 teaspoon black pepper
1/4 cup grated Parmesan cheese for topping