Preheat the oven to Gas 4/180°C/fan 160°C. Grease the base and sides of two 20cm round cake tins. Line the bases with baking paper.
Beat the butter and sugar with an electric whisk until light and creamy. The longer you beat, the fluffier your sponges will be.
Add the treacle, syrup, eggs, egg yolks and gingerbread syrup and mix until well combined.
Sift together the flour, spices, baking powder and salt. Add to the wet ingredients in two batches, alternating each time with the warmed milk. Beat until nicely combined.
Divide the mixture between the two tins. Bake in the oven for 25 mins, or until the sponges are risen and golden and a skewer inserted into the centre comes out clean. Leave the sponges in the tins while you make the coffee syrup.
Brew your coffee for the coffee syrup. Add it to a bowl and stir in the sugar. Keep stirring until the sugar is dissolved and doesn’t feel grainy in the bowl. Drizzle or brush the syrup over the surface of the sponges. You want to use around three or four tbsp of the syrup per sponge – you’re not trying to flood them! Remove from the tins when cool.
Next, make the gingerbread buttercream. Beat the butter for about five minutes until soft and very pale. Add the gingerbread syrup.
Sift the icing sugar and add it gradually to the butter mixture. Beat well after each addition. If your frosting is a little stiff once you’ve added all the icing sugar, beat in a dribble of milk.
Remove the sponges from the tins and spread buttercream on one of them. Pop the second on top and decorate with the rest of the buttercream. Finish with sprinkles and serve!