For the sponge (makes four mugs)Ingredients250ml stout 250g unsalted butter 75g caster sugar 142ml sour cream 2 large eggs 1 tbsp vanilla extract 275g plain flour 2½ tsp bicarbonate of sodaMethod This makes one flat rectangular sponge approx. 30cm by 20cm in size.Preheat the oven to gas mark 4/180°C/350°F, and butter and line the tins.Pour the stout into a large wide saucepan, add the butter – in spoons or slices – and heat until the butter has melted. Then immediately whisk in the cocoa and sugar.Beat the sour cream with the eggs and vanilla and then pour into the brown, buttery, beery mixture and finally whisk in the flour and bicarb.Pour the cake batter into the greased and lined tins and bake for 30-35 minutes. Leave to cool completely in the tin on a cooling rack, as it is quite a moist cake.Chill the sponge in the fridge for 30 minutes before cutting out discs with a circle cutter. To make each mug you will need three discs (12 in total).For the chocolate swiss meringue buttercreamIngredients4 egg whites (125g) 225g sugar 175g unsalted butter (room temperature) 150g melted dark chocolateMethod To make the meringue, place the egg whites and sugar in the stainless steel bowl of your food mixer and stir over a pan of water (making sure the base of the bowl does not touch the water).Warm at a moderate heat until the mixture is hot and the sugar has dissolved (around 65°C if you have a thermometer). The sugar and heat kill off any bacteria and effectively sterilise the mixture.Re-attach the stainless steel bowl to your food mixer and whisk for 5 minutes until the meringue is thick, holding its shape and cooled. If you don’t have a food mixer you can use a metal or Pyrex bowl and an electric whisk.Melt the chocolate (either in the microwave or over a pan of water) and allow it to cool a little. Add this to the meringue and beat it in, until fully mixed. Beat the butter into the meringue in small cubes. Stop whisking when the butter is thoroughly mixed through and the mixture has thickened.For the fondant decorationIngredientsYellow fondant Cake Angels mini marshmallowsTo assemble Use the chocolate buttercream to stack the discs in threes to create little pillars. Then cover all around the outside with buttercream and smooth the sides and top. Chill for at least an hour while you create the fondant decoration.Roll four sausage shapes and form into handles with flat ends ready to attach to the mug. Leave to harden.Roll the remaining fondant flat and cut out four rectangles slightly bigger than the cake pillars. Make imprints with a spoon handle to create the shape of a pint glass. Carefully wrap the fondant rectangles around the cake pillars, trim to fit and seal with water.Use water to attach the handle and prop up to allow it to stick while it dries overnight.Fill the space between the top of the cake and the top edge of the fondant with white marshmallows. Banbury-based baking decorations supplier Cake Angels has come up with a way to offer dads a treat combining cake and beer. Cake Angels has put together the video to celebrate Father’s Day. And if you want to recreate the magic yourself, the recipe is below.