Preheat the oven to 180ºC/350ºF/gas 4 and grease a small ovenproof dish (23-25cm) with butter.
Mix the cocoa powder with a few tablespoons of boiling water and stir until the mixture is lovely and smooth.
In another bowl or a food mixer, beat the butter and sugar together until fluffy and light, then add the cocoa mixture, egg, flour and baking powder. Mix it all together really well, pour into your ovenproof dish and sprinkle the cherries and hazelnuts on top before putting in the oven for about 25 minutes.
While your cake is baking, make your chocolate sauce. Place the butter in a small pan with the cream and bring to the boil. Turn off the heat and add your chocolate pieces to the pan. Give it all a good stir and then leave it for 5 minutes so that the hot cream can melt the chocolate. Add a splash of your desired alcohol and stir until thoroughly combined.
To check if your cake is ready, give it a bit of a jiggle and if it doesn’t wobble too much then it’s done, if not, give it a few more minutes in the oven.
Once it’s ready, pour your warm chocolate sauce all over the cake and either share it right from the dish or serve it up on two small plates with vanilla ice cream or double cream. Delicious!