Chop the onions and sauté in the butter until transparent.
Grind the nuts and bread together in a liquidizer until quite fine.
Heat the stock and yeast extract to boiling point, then combine all the ingredients together and mix well – the mixture should be fairly slack.
Turn into a greased shallow baking dish, level the surface, sprinkle with a few breadcrumbs, and bake in the oven at 180°C (350°F/ Mark 4) for 30 minutes, until golden brown.
Garnish with fried onion rings, if wished.