Queen Elizabeth’s Favorite Chocolate Biscuit Cake

Lightly grease the cake ring or springform pan with butter, and place on a baking sheet on top of a sheet of parchment paper.

Beat the butter and sugar until light and fluffy. Melt the 4 ounces of dark chocolate either in the microwave (in 30-second spurts, stirring in between) or in a double boiler, and add to the butter mixture, beating to combine. Beat in the water, then fold in the biscuit pieces to coat with chocolate.

Spoon the mixture into the prepared cake ring or springform pan. Carefully but firmly push the mixture down with the bottom of a drinking glass to create an even texture. Refrigerate for at least 3 hours.

Place the 8 ounces chopped chocolate into a bowl. In a small saucepan over medium heat, bring the cream to a simmer, then pour it over the chopped chocolate, stirring until the chocolate melts and the ganache is smooth.

Remove the cake from the refrigerator and from the cake ring or springform pan. Place it on a wire rack with a tray beneath to catch the excess ganache. Carefully pour the warm ganache over the cake, smoothing it with an offset spatula. Allow the cake to sit at room temperature to set.