Weigh the tongue and soak overnight in cold water.
The next day, drain the tongue and transfer to a pressure cooker. Add the mace, onion, peppercorns and carrots and add water to half-cover contents. Cook for 15 minutes per 450g (1 lb).
Transfer the tongue and the stock from the pressure cooker to a saucepan, top up with water to cover and cook for 4 hours. Continue adding water if necessary.
Take tongue from the stock and allow to cool some. Reserve stock. Skin and remove any small bones from the tongue.
Curl tongue into a round 15cm (6 in) straight sided dish or tin and spoon over 4 tablespoons reserved stock. Cover with cling film and set a heavy weight on top. Leave tongue overnight to chill in the fridge. Pour the stock into a measuring jug, cover and store in the fridge.
The next day, remove tongue from dish, cut in half and slice.
Preheat oven to 180 C / Gas 4.
For the sauce:
In a saucepan, melt the margarine and add the chopped carrot and onion. Cook and stir gently for 5 minutes until soft. Remove from the heat, add flour, stir well and add wine and 300ml of the reserved stock. Return to heat and stir until boiling. Add jelly, raisins and almonds, season well.
Arrange sliced tongue on a baking dish and pour the sauce down the centre. Cover with foil.
Bake for 40 minutes before serving.
For a first timer, cooking an ox tongue may be a little confusing. Here are some tips:
1. Search for a fresh, small ox tongue. Around 1.5kg (3 lb) or under is usually best in terms of flavour.
2. Clean the tongue well by scrubbing it and allowing it to soak in fresh water.
3. Don't try to cook it too fast, otherwise it can toughen; slow and steady is good.
4. Tongue is not a lean meat, so you will need to remove the skin and the roots from the back.
5. Once cooled, slice very thinly for an an excellent treat on sandwiches or in other dishes.