Place duck breast in roasting tin, pour oil over, and cook in a pre-heated 250C oven for 20 minutes. Cool, remove skin and dice the breast meat. Put speck, liver, salt, pepper, quatre spices, cream, egg yolks and armagnac into a liquidiser and blend until smooth. Pour into a bowl and add the diced duck breast meat. Taste for salt and pepper. Pour mixture into an earthenware terrine, cover well, and cook in a bain-marie for 30 minutes in a pre-heated 250C oven. Terrine should be 5 cm thick. Allow to cool, then place in refrigerator for 24 hours before serving with a spoon straight from the dish. Serve with hot toast, freshly ground pepper and garnish with warm bunches of grapes. To make garnish: melt sugar and butter in a frying pan. Add grapes and toss quickly for a few seconds. Flame with armagnac and serve warm, This terrine is wonderful served with a chilled sauternes.