Christmas Bobble Hat Cake

Method

1. Preheat the oven to 180˚C/Gas 4. Grease and line the hemisphere and round cake tins with baking parchment.
2. Cream together the margarine and caster sugar until light and fluffy. Beat in the eggs one by one and then sift in the flour and baking powder. Mix together, along with the vanilla extract.
3. Divide the mixture between the tins until they’re both three-quarters full and bake in the oven – 35-45 minutes for the round cake and 60-80 minutes for the hemisphere cake. Check if they are cooked through by inserting a toothpick into the centre of the cakes – it should come out clean. Turn out onto a wire rack to cool. Cut off any domed tops from the cakes so that they are level before moving on to the decoration.
4. Take a cake stand or cake board and attach the round cake to it with a small blob of the vanilla frosting. Spread a layer of raspberry or strawberry jam on the top of the cake, followed by a thin layer of frosting. Place the hemisphere cake on top and cover the whole cake with a crumb coat of frosting. Put the cake in the fridge for 30-60 minutes to chill.
5. Take 250g of white icing and roll it into a long, thin sausage. Roll it flat with a rolling pin and cut a strip 4cm wide – this needs to be long enough to wrap around the base of the cake to make the band. Use a blunt knife or toothpick to make indentations along the whole length and attach the strip to the base of the cake.
6. To make grey marl 'wool', knead a bit of grey icing in with white icing until it has marbled together. Work with a golf ball-sized amount of icing at a time.
7. To make the knitted part of the hat, roll two long thin ropes, 20cm long and 5mm thick, and twist them together clockwise. Starting from the top of the cake, attach the rope all the way down over the curve to the top of the band, trimming off any excess icing where it joins the band.
8. Roll another two ropes and twist these in the opposite direction (anti-clockwise). Attach this next to the previous rope, so you have one knitted column. Repeat this process all the way around the cake until it is completely covered.
9. To make the bobble on top, roll white icing into a golf ball-sized ball, and stick in place on top of the cake with a blob of royal icing. Finally, using a piping bag fitted with a small round nozzle, pipe royal icing spikes all over the bobble.