In a large saucepan or pot heat the olive oil over a medium to high heat. Add the diced onion, carrot and crushed garlic. Sauté for a bout 5 minutes until the vegetables have started to soften.
Add the ground beef/ beef mince and continue to cook whilst stirring until all the meat has been browned off.
Add the Worcestershire sauce, mustard, soy sauce, stock and tomato paste. Give it a good stir and simmer over a medium heat for 15-20 minutes. Stirring occasionally.
Melt the butter either in the microwave or on the stovetop, and stir in the flour to form a thick paste. Add to the beef mixture and stir well. Remove from heat and stir for a couple of minutes until the sauce has thickened up nicely.