Best Homemade Sloppy Joes

In a large skillet over medium-high heat, cook ground beef and yellow onion together, stirring occasionally, until beef is browned and cooked through.

Drain any excess fat from the skillet and return skillet to heat.

Add in bell pepper, celery, tomato sauce, tomato paste, Worcestershire sauce, garlic, brown sugar, salt, ground mustard, and red pepper flakes. Stir to combine.

Bring to a simmer and reduce heat to medium low. Simmer for 15 to 30 minutes. Simmering time depends on how crisp you want the vegetables.

Serve meat hot on toasted buns.