Heat the oven to 180C/160C fan/gas 4. Line two 20cm square tins with baking parchment. Beat the butter and sugar together in a large bowl using an electric whisk for 2-3 mins until smooth and creamy. Crack in the eggs, one at a time, adding a spoonful of the flour between each addition and whisking continuously. When all the eggs are incorporated, tip in the remaining flour and fold it in. Pour in the milk and vanilla and mix well, making sure there are no pockets of flour.

Divide the batter between the tins, smooth the surfaces and bake for 40 mins until risen, golden and a skewer inserted into the middles comes out clean. If any wet batter clings to the skewer, bake for 5 mins more, then check again. Once baked, cool in the tins for 20 mins, then transfer to a wire rack to cool completely. Once cooled, the sponges will keep wrapped in the freezer for three months.

For the buttercream, beat the butter, 500g icing sugar, the milk and vanilla in a bowl using an electric whisk until smooth and creamy. Cut out a roughly 14cm circle of baking parchment, scrunch it up and use it to line a 12cm bowl. Spoon half the buttercream into the bowl, gently pushing it down and smoothing the surface. Cover and freeze for 15 mins to firm up.

Cut the sponges in half through the equator using a long, serrated knife to create four layers. Put one on a plate or cake stand, spread over a quarter of the remaining buttercream, spoon over a third of the jam and sandwich with a second layer of sponge. Repeat with the rest of the sponge layers, using most of the remaining buttercream and the rest of the jam. Spread the last of the buttercream over the top and sides of the cake (don’t worry if it isn’t neat).

Dust a surface with icing sugar and tip the fondant out. Add a few drops of the food colouring, kneading it in with your hands until the fondant is evenly pink. Roll it out into a roughly 60 x 60cm square.

Invert the frozen buttercream dome on top of the cake and remove the parchment. Carefully lift the fondant over the cake, using your hands to smooth it over the dome and down the sides. Use a sharp knife to trim any excess fondant.

Mix the 3 tbsp icing sugar with enough water to make a thick, drizzly icing. Spoon into a piping bag, snip off the tip and drizzle it back and forth over the cake, then leave to dry for a few minutes. Will keep in an airtight container for three days.