In a pot, add ground beef and olive oil. Sauté over medium heat until beef is cooked through, about 5 minutes. Drain excess fat if needed.

While beef cooks, finely dice the onion. Add the diced onion and butter to the pot with the beef. Sauté until onion is soft and translucent, about 5 minutes.

Stir in the crushed tomatoes, Italian seasoning, and freshly cracked black pepper.

Place a lid on the pot and bring the sauce to a simmer. Reduce heat to low and let it simmer for at least 30 minutes, stirring occasionally.