Melt butter in a skillet, sauté diced onion and garlic paste until soft.
Add ground beef and cook until fully browned, breaking apart into crumbles.
Stir in tomato sauce, vinegar, sugar, salt, and water.
Simmer on medium-low heat for 12 minutes until the sauce thickens into a rich, savory meat filling.
Toast burger buns, spoon the warm sloppy joe mixture generously onto buns, and serve.