In a large saucepan or Dutch oven over medium-high heat, combine beef and onion. Cook until the meat is mostly browned, about 5 minutes. Drain well.
Meanwhile, in a small bowl whisk together tomato sauce, ketchup, brown sugar, vinegar, Worcestershire, mustard, and salt and pepper to taste (I like 1/4 teaspoon salt and 1/8 teaspoon pepper).
Pour sauce ingredients over drained beef and stir until evenly coated. Simmer uncovered 20 minutes, stirring occasionally (cover if you prefer a sloppier Sloppy Joe). Serve in buns.
Video
Notes
Ground beef: Or substitute ground turkey or venison.
Onion: Finely chopped celery and bell peppers are great too!
Brown sugar: Even a tablespoon is too much for some people. If you don't like the sound of brown sugar in your Sloppy Joe, please leave it out!
Worcestershire sauce: In a pinch, you can substitute soy sauce.
Yield: This recipe makes 4 to 6 cups of Sloppy Joe meat mixture, enough for 8 heaping sandwiches.
Storage: Store covered in the refrigerator for up to 4 days.
Freezer: Cool completely, then add to freezer containers (one big batch or individual portions), label and date, and freeze for up to 4 months. Thaw overnight in the refrigerator.