Preheat oven to 200℃ (Gas 6).
Peel and chop the potatoes into quarters and put them into a pot to boil. Boil for around 20-30 minutes until soft enough to mash.
Finely chop the onion and the garlic and fry in a little rapeseed oil for about 5 minutes.
Add the mince and fry until brown.
Remove, mince, onion, and garlic from the frying pan and place into an oven-proof dish.
Chop and baton the carrots, and slice the celery and red pepper. Add them to the mince, you don't need to fry them.
Add the rest of the ingredients, tin of tomatoes, stock cube, herbs, tomato puree, and gluten-free Worcester sauce (if using).
Add a pinch of salt and pepper.
You can add (300ml) or 1/2 pint of water if the mixture looks a little dry.
Mash your warm potatoes, I like to use a knob of butter and a splash of milk (this is optional).
Add the mash to the top of your mince and vegetables and firm down with a fork. You can add herbs and grated cheese if you wish or leave it plain.
Now pop into the oven and bake for 30-40 minutes or until the top is browned. Serve with a little beef gravy. Heaven.