Heat a large non-stick frying pan over a medium heat. Tip in the mince and cook for about 5 minutes until well browned, breaking up any lumps with a wooden spoon.
Remember to wash your hands with warm soapy water after handling raw meat.
Using a small sharp knife, cut the onion in half and peel off the skin, then cut into slices, discarding the root.
Cut the pepper in half and remove and discard the core and seeds, then cut into bite-sized pieces. Trim the mushrooms and cut into slices.
Add the vegetables to the mince, stirring to combine. Season lightly with salt and pepper if using and cook for another 3-4 minutes until the vegetables are softened.
Sprinkle the herbs over the mince and vegetable mixture and then stir in the tomato puree and cook for another minute, stirring.
Pour in the stock and allow to bubble down, then add the tomatoes and Worcestershire sauce.
