Heat butter and oil, letting butter start to brown.
Add onion halves cut side down and let brown about 2 mins.
Add tomatoes and break into smaller pieces.
Add salt, basil oil "goodies" and cheese rind.
Carefully, add meatballs.
Raise heat to a boil then cover and simmer on low 1 hour.
Remove onion halves and cheese rind after the hour.
Crack lid a drop and simmer another hour on very low.