Step 1

Heat the oven to 170°C/150°C fan/gas 3½. In a medium saucepan, gently heat the butter and caster sugar, until the sugar has dissolved into the melted butter. Turn off the heat and add the milk.

Step 2

Sift the cocoa powder and flour into a large mixing bowl. Make a well in the middle and pour in the milk mixture and the beaten eggs. Whisk to make a smooth thick batter. Pour the batter into the prepared baking dish.

Step 3

For the sauce, mix together the cocoa powder and sugar in a small bowl, then pour over the boiling water and stir until the sugar dissolves. Pour the sauce evenly over the top of the cake batter, then press in the Daim pieces. Put the baking dish on a shallow oven tray (to catch any drips and prevent the bottom from overcooking) and bake for 30 minutes. Remove from the oven and leave to stand for 5 minutes before serving with cream or ice cream.