Heat the vegetable oil in a large cast iron skillet over medium-high heat. Add the ground beef and cook for 3-5 minutes, breaking it apart as it browns. Drain any excess fat.

Add the onion and bell pepper, cooking and stirring occasionally until softened, about 3-4 minutes.

Mix in the tomato paste, garlic, paprika, chili powder, and cayenne pepper, stirring until fragrant, about 1 minute.

Pour in the beef stock, scraping up any browned bits from the skillet’s surface.

Add the ketchup, Dijon mustard, Worcestershire sauce, and brown sugar. Season with salt and pepper to taste. Bring the mixture to a boil, then lower the heat and let it simmer, stirring occasionally, until the sauce thickens and the flavors meld, about 15-20 minutes.

Serve right away.