With so few ingredients, Rachel Allen’s simple cake is all about the buttery deliciousness – perfect with a cuppa.
Preheat the oven to 180C/160C fan/gas 4. Butter the sides of a 25cm cake tin and line the base with a disc of baking parchment.
Whisk together the egg yolk with 2 teaspoons of water for the glaze and set aside. Either in a large bowl using a wooden spoon or in an electric food mixer using the paddle beater, mix together the flour and sugar, then add the butter and egg yolks and beat together until the mixture resembles a stiff dough.
Press into the prepared tin, and flatten with a spatula. Brush with the glaze, then decorate by drawing a fork across the cake in a criss-cross pattern of lines, each set of lines roughly 5cm apart in a sort of chequerboard design, following the traditional style for the cake.
Bake for 30 minutes, or until it is a deep golden colour and a skewer inserted into the centre of the cake comes out clean. Remove from the oven and allow to cool in the tin for 10 minutes, then loosen the edges using a small, sharp knife and carefully remove the cake from the tin before placing on a wire rack to cool down completely.