Heat a 4-qt saucepan over medium heat and add the olive oil and butter. Once hot and butter has melted, add the minced garlic, salt and pepper and stir, cooking for 1 minute. Add in the tomato paste and stir, cooking for another 1 to 2 minutes. Pour in the beef stock and stir until the tomato paste is dispersed through the stock and the mixture is smooth and thick, about 5 minutes. Bring to a simmer and stir in balsamic vinegar and 1/2 teaspoon sugar. Taste and season with additional salt, pepper, and sugar if needed (optional). Reduce heat and cover with a lid.
While sauce simmers, make meatballs: To a bowl add ground beef, spices and egg. Mix gently to combine. Roll meat into small 3/4-inch balls. Place meatballs into sauce and continue to simmer on low, covered. Cook until the meatballs are cooked through, 8-10 minutes.
While the meatballs are simmering, cook the pasta according to the package directions in a large pot of salted water. When al dente, drain well and rinse immediately with cold water (to stop the pasta from cooking any longer) and top with the mini meatball sauce, stirring to combine everything together. Top with fresh Parmesan cheese and basil, if desired and dig in.