Roald Dahl's Great Glass Elevator cake

Bake the sponge mixture in a 2L Pyrex bowl. Remove from the oven and reduce the temperature to 160C/140C Fan/Gas 3. Let the cake cool.

Make a biscuit dough. Melt the butter, sugar and golden syrup in a pan on a low heat, stirring. Add the vanilla, then mix to a dough with the flour and egg. Wrap in clingfilm and set aside to rest for 30 mins

Line a baking sheet with baking paper, then cut out templates from more baking paper – a 7cm square and a 7cm x 10cm rectangle.

Roll out the biscuit dough to 5mm thick, then use the templates to cut out 2 squares and 4 rectangles. Arrange on the lined baking tray.

Using a sharp knife, remove the centre of each biscuit to leave a 6mm ‘frame’. Place 5 mints, evenly spaced, inside each rectangle and 3 mints in each square. Bake for 6-7 mins, until the mints have just melted and spread out like panes of glass, and the biscuit is pale golden. Leave to cool on the baking sheet.

Trim both sides of the cake a little, to give each a flat, level surface. Arrange, wide-end down, on a plate. Split in half, spread with the jam, then sandwich back together. Cover with the blue frosting. Roll out the green icing, cut out continents and islands, then arrange on the frosting.

Make 4 little pyramids, plus one big one, from the white icing and put on baking paper. Spray with the gold shimmer and leave to dry.

Mask the mint ‘windows’ with pieces of baking paper, then spray the frames with gold shimmer. When all the pieces are dry, assemble the elevator. Use basic royal icing to stick the 4 rectangular sides together around the square floor, then add the roof. Decorate the roof with a small pyramid at each corner and the large one in the centre. Spray a little gold shimmer on a plate and paint over any white icing with a small brush.

Position the elevator on the cake just before serving.