Take a large skillet and heat some oil and heat on the medium/high heat. Add the beef and brown, keep cooking for 5 minutes and break it apart into crumbles. And to drain, shift it to a colander.
In the same skillet, add bell pepper and onion, cook until it becomes soft, and for 2-3 minutes more. Afterward, pour some garlic and keep cooking until it becomes fragrant or for 30 seconds more. Put the beef back in the skillet and mix some tomato paste in it. Blend it nicely by stirring well.
Pour water, mustard, Worcestershire sauce, ketchup, red pepper flakes, brown sugar, salt, black pepper, and chili powder. Combine it well by stirring.
Cook it until the mixture becomes pretty much thick as you want or for 10-15 minutes on medium heat.
Take it from the heat source and serve!