Heat the oil in a large skillet over medium-high heat. When hot, add the ground beef, breaking it up into large chunks, but leaving it alone otherwise for a minute or two to sear on the bottom. Once the ground beef has started to develop a crust on the bottom, continue to break it up and cook until browned through. Drain off excess grease, if necessary.
1 tablespoon olive oil, 1 pound lean ground beef
Add the onion, chopped bell pepper, and garlic. Season with salt and pepper, then cook for 5-6 minutes, stirring frequently, until softened.
1/2 yellow onion, 1/2 red, yellow, orange, or green bell pepper, 2 cloves garlic, 1 teaspoon Kosher salt, 1/2 teaspoon freshly ground black pepper
Add tomato sauce, beef broth or water, ketchup, tomato paste, mustard, cider vinegar, Worcestershire sauce, brown sugar, chili powder, smoked paprika, ground cumin, and red pepper flakes. Mix until combined.
1 (8-ounce) can tomato sauce, 1/2 cup beef broth or water, 1/3 cup ketchup, 1 tablespoon tomato paste, 1 tablespoon yellow mustard, 1 tablespoon apple cider vinegar, 2 teaspoons Worcestershire sauce, 2 tablespoons brown sugar, 1 teaspoon smoked paprika, 1/2 teaspoon chili powder, 1/4 teaspoon ground cumin, 1/4 teaspoon red pepper flakes
Reduce the heat to medium-low and simmer for 5-10 minutes, stirring occasionally, until thickened but saucy.
Serve on your favorite buns. A slice of cheese and pickles on top are optional, but delicious!