A delicious flourless chocolate cake by Laura Calder.
Heat the oven to 375°F/190°C. Line with parchment, grease, and flour an 8-inch/22 cm springform pan.
Melt the chocolate gently over a water bath, then beat in the butter a piece at a time until smooth. In a separate bowl, beat the yolks with half the sugar until thick, pale, and ribbony. In yet another bowl, beat the whites to peaks. Scatter over the remaining sugar and beat to a stiff meringue.
Slowly whisk the chocolate mixture into the yolk mixture. Stir in a spoonful of egg white, then pour the chocolate mixture over the egg whites and gently fold together with a spatula. Pour the batter into the prepared pan and bake 50 minutes.
Remove from the oven. Run a knife around the outside edge, then let sit until cool. It will sink down and the top will crack, appealingly. Serve with a drift of slightly sweetened whipped cream, flavoured with vanilla, rum, or orange flower water.