Add the olive oil and butter to a large skillet and heat on medium-high until the butter is melted.
Add the onion and sauté until almost soft and clear, then add the garlic and sauté for 1 or 2 minutes more.
Add the beef and cook until it’s no longer pink—stirring often.
Add the cherry tomatoes, cover and cook on medium-high heat—stirring occasionally. When the cherry tomatoes start to burst, use a potato masher to mash them in the skillet.
Add the tomato sauce, oregano, rosemary, thyme, basil, salt and pepper.
Reduce the heat to medium-low and simmer, uncovered, until the sauce reaches the desired consistency.
Serve over pasta. Sauce may be doubled and frozen for easy weekday meals.