Add oil to a large skillet. Place skillet over medium heat.
When oil is hot and shimmering, add onions. Sauté onions until they are translucent and fragrant.
Add beef. Cook beef, using a wooden spoon to break apart, until fully browned.
Stir in Italian seasoning, salt, pepper and garlic powder.
Add tomatoes, tomato paste and garlic. Stir well.
Add alcohol if using.
Adjust heat to get a good simmer going. Cover and let cook for 2 hours or more, stirring occasionally and add water if needed, so the bottom doesn't burn.
Taste. Add more salt and pepper, to taste, if needed.
Serve hot over spaghetti or other pasta or as a dipping sauce for bread or appetizers.
Store any leftovers in a tightly sealed container, in the refrigerator, up to a week. This sauce reheats well.