Whisk ketchup, water, white sugar, brown sugar, vinegar, mustard, salt, pepper, and paprika together in a large saucepan. Bring to a simmer over medium high heat; reduce heat to medium low and simmer 15 minutes.
Meanwhile, heat a large skillet over medium high heat. Add ground beef and onion; cook and stir until beef is crumbly, evenly browned, and no longer pink. Drain and discard excess grease. Stir beef into simmering barbecue sauce; continue to simmer for 10 minutes. Serve on buns.
Nonie's Best BBQ · Dinner Match Lab | Dinner Match Lab