Step 1

Preheat the oven to 180C/160C fan-forced. Line the base of a 19 x 29cm slice pan with baking paper, allowing the paper to overhang 3cm on each long side.

Step 2

Base: Use electric beaters to beat the butter, sugar and egg in a bowl until pale and creamy. Fold in the sifted flours until combined. Spread the mixture into the base of the prepared pan, smoothing the top. Bake for 20-25 minutes or until golden. Set aside to cool.

Step 3

Mock cream: Meanwhile, for the mock cream, stir the sugar, milk and 80ml water in a small saucepan over low heat, without boiling, until the sugar dissolves. Sprinkle the gelatine over the sugar mixture and stir until the gelatine dissolves. Set aside to cool to room temperature. Mixture will thicken slightly.

Step 4

Use electric beaters to beat the butter and vanilla in a bowl until very pale. With the motor running, gradually beat in the cooled milk mixture, beating until pale and creamy.

Step 5

Spread the cooled pastry base with jam. Top with the mock cream, smoothing the surface. Place in the fridge until required.

Step 6

Glace icing: For the glace icing, sift the icing sugar into a bowl. Stir in the butter, vanilla and slowly add the milk to make a thick icing (you may not need it all). Divide the icing evenly between two bowls. Tint the icing in one bowl with pink colouring. Sift the cocoa into the other bowl of icing until combined (you may need to add a little more milk, if necessary) until the icing is a spreadable consistency.

Step 7

Use a ruler to divide the slice in half, lengthways, and run a knife down the middle to lightly mark. Mark another two lines down the middle of each half (you will have 4 even strips running lengthways across the slice). Spoon each batch of icing into a snap lock bag. Snip off one corner. Use the pink icing to mark out the edges of the two outside strips and then fill with icing. Repeat with chocolate icing to mark out and fill the remaining middle strips (see note). Set aside for 15 minutes or until set. Use a hot knife to cut the slice down the middle and then into slice into thin fingers, with a pink and brown iced half on each finger.