Add butter to the olive oil in the pan you used to cook the sausages. Add onions, salt, pepper, dried oregano and dried basil. Cook on low to medium low for 5 minutes.
Add all the peppers and the garlic. Combine and continue to cook for another 5 minutes.
Return sausages to the pan, stir and cook for another 5-10 minutes or until everything is tender and combined. Taste and adjust seasoning.