Gently fry the onion, carrot and mushrooms in a large frying pan or wok
Cook the lentils in the stock and reduce the liquid to about 250 ml
Add the cooked lentils, borlotti beans, hazelnuts and almonds to the onion mixture.
Gently fry the buckwheat and rolled oats for a few minutes, then add to the other mixture with the soy sauce, lemon juice, suet, gravy browning and black pepper simmer for a few minutes until the liquid begins to disappear
Turn into an oven proof dish and allow to stand for 20 mins then cook in a medium oven for 30 mins