The lid has finally been lifted on what Prince William and Kate Middleton have planned for their Royal Wedding — the couple announced that they will be having more than one wedding cake, they’ll be eating two. Celebrity cake designer, Fiona Cairns has been commissioned to create the main cake, which is a multi-tiered traditional fruit cake. The second cake is less formal. It’s a Chocolate Biscuit Cake which is said to be Prince William’s childhood favourite. However, Princess Diana's personal chef Darren McGrady has announced that he holds the key to Prince William's Royal Wedding cake recipe. When many are speculating about the ingredients of Chocolate Biscuit Cake, McGrady offers the true recipe in his cookbook 'Eating Royally'. Darren McGrady's cookbook 'Eating Royally' "I was thrilled to learn that Prince William had chosen the Chocolate Biscuit Cake recipe from my book Eating Royally: Recipes and Remembrances from a Palace Kitchen, for his wedding cake because it is also his grandmother's favorite cake," says McGrady. "I used to prepare it for both of them when they had tea together. The Queen would request the cake in the menu book for Sunday tea when she knew her grandson William would be joining her from Eton." Chef Darren McGrady William asked British biscuit maker McVitie’s, who have made several wedding cakes for the royal family before, to produce the cake according to a special recipe from the kitchen at Buckingham Palace, containing Rich Tea biscuits and dark chocolate. The mixture is set in the freezer rather than baked and will use a whopping 1,700 biscuits and nearly 40lb of chocolate. Cake Design and Development Head Chef Paul Courtney tastes a trial biscuit cake at the McVitie's factory, which is being made as an alternative royal wedding cake The cake for the reception will consist of 1,700 biscuits and nearly 40 lbs. of chocolate. McVitie's has been given the recipe for the concoction, although there are some mysteries associated with the royal version. "It has a couple of secret ingredients we can’t tell you about but it will have dark chocolate, to give it a really nice flavor, and use Rich Tea biscuits that will be broken up," according to Paul Courtney, McVite's development head chef. "It will be decorated with chocolate display work which will be contemporary, modern and elegant. The company will be serving "a few hundred" slices for the party guests at the Royal Wedding Reception. Prince Williams Chocolate Biscuit Cake Serves 8-10 Recipe courtesy of Darren McGrady 'Eating Royally' 1/2 tsp butter, for greasing pan 8 ounces 'McVities' rich tea or 'Digestive' biscuits 4 tablespoons unsalted butter, softened 1/2 cup granulated sugar 4 ounces good dark chocolate 1 egg, beaten 8 ounces good dark chocolate, for icing 1 ounce good white chocolate, for decoration Optional (my suggestion): 2oz whole walnuts 2oz sultanas 2oz maraschino cherries Lightly grease a small 6" x 2 1/2" cake ring with 1/2 teaspoon butter, and place on a parchment-lined tray. Break each of the biscuits into almond-sized pieces by hand and set aside. Cream the butter and sugar in a bowl until the mixture is a light lemon colour. Melt the 4 ounces of dark chocolate in a double boiler. Add the butter and sugar mixture to the chocolate, stirring constantly. Add the egg and continue stirring. Fold in the biscuit pieces until they are all coated with the chocolate mixture. Add the walnuts, sultanas and cherries for a fuller flavoured cake, if you desire. Spoon the chocolate biscuit mixture into the prepared cake ring. Try to fill all of the gaps on the bottom of the ring, because this will be the top when it is unmolded. Chill the cake in the refrigerator for at least three hours. Remove the cake from the refrigerator, and let it stand while you melt the 8 ounces of dark chocolate for icing. Slide the ring off the cake and turn the cake upside down onto a cooling rack. Pour 8 ounces of melted dark chocolate over the cake, and smooth the tope and sides using a butter knife or offset spatula. Allow the chocolate icing to set at room temperature. Carefully run a knife around the bottom of the cake where it has stuck to the cooling rack, and transfer the cake to a cake dish. Melt the white chocolate and drizzle on top of the cake in a decorative pattern. Serve chilled. Princess Diana'a Bread Butter Pudding Makes 8 servings 12 slices of white bread (8 into triangles, 4 into cubes) 4 oz softened unsalted butter 9 egg yolks 5 oz caster sugar 1 vanilla pod 5 fl oz milk 15 fl oz double cream 3 oz raisins 3 oz flaked almonds (toasted) 4 tablespoons of Amaretto or Cointreau 1 oz extra caster sugar (for the top of the pudding) 1 teaspoon of Icing sugar Soak the raisins the night before in the Amaretto and cover with cling film. Leave at room temperature. Preheat the oven to 350degrees. Grease a 3 pint dish with butter. Remove the crusts and butter the bread. Whisk the egg yolks and the 6 oz caster suger in a bowl together. Split the vanilla pod and put in a pan with the milk and cream, then bring to a simmer and pour onto the egg yolks, stirring all the time. Remove the vanilla pod, scraping the seeds into the custard and discard the pod. Cut a quarter of the bread into 1/2 inch cubes and place in the bottom of the dish. Then top with the raisins adding the juices too. Finish with the remaining bread cut into triangles and arranged on top of the fruit. Pour the warm egg mixture over the bread making sure all of the bread is coated. Leave to soak into the bread for 20 minutes. Place in the oven in a roasting tray 3/4 full of hot water. Cook for about 30 minutes. It will only set like custard because of using egg yolks and no whites. Remove from the oven and roasting tray and sprinkle with the extra sugar. Then put under the grill until the sugar starts to caramelize. Sprinkle with the toasted flaked Almonds and dust with icing sugar. The pudding is now ready to serve. I usually serve it just warm with homemade cinnamon or lavender ice cream and a compote of berries – and lots of heavy cream of course.