Cook pasta according to directions on the back. Drain and reserve 1 cup of pasta water. Heat butter and oil over medium heat. Add onions and garlic and saute for about 1 minute. Pour in the tomatoes sauce. Then season with salt and pepper and sugar to taste. Stir and cook on low for 25-30 minutes. Stirring occasionally.
Remove from heat and stir in the heavy cream. Add cheese to taste and then check to see if you want to add any more seasoning (salt, pepper, sugar) Add pasta water a little at a time if you need to thin the sauce. Then stir in pasta and chopped bail and serve immediately.