Jólabrúnkaka

Mix all the ingredients together in a stand mixer until a thick dough forms.

Divide the dough into 4 equal parts and roll each part out on baking paper (the same size as the oven tray the cake will be baked in). See image below. It’s best to place the dough on the baking paper and spread it out with your hands to begin with. Then place another sheet of baking paper on top and roll it out with a rolling pin to make it even and smooth.

Bake each dough layer at 175°C (using top and bottom heat, not convection) for about 10 minutes, on the bottom rack of the oven. Let the layers cool completely.

Mix powdered 1 kg sugar and 500 gr of soft butter and 1 teaspoon of vanilla extract well together. Add the 4 egg yolks one at a time and mix thoroughly until the frosting is smooth.

Divide the frosting into three equal parts and spread between the cake layers, stacking them one on top of the other with frosting in between. Finish with a cake layer on top. Trim the edges and cut the cake into about 8 equal pieces (this is up to personal preference). To soften the cake slightly before cutting, you can place a damp tea towel over it for a little while. The cake keeps very well in the freezer.