Preheat the oven to 180C or 160C if using a fan oven. Line a 20 x 20cm square tin with parchment paper, leaving a little paper hanging over the sides.
To make the shortbread base, put the butter, sugar, and flour in a food processor and blend until the mix resembles fine breadcrumbs. Add the water, and when the dough just comes together, remove from the processor and work by hand for a minute until a ball forms.
Press the base into the prepared tin and place in the freezer for five minutes.
For the Jam Layer:
When the shortbread base is cold, spread the jam on top and set aside.
For the Frangipane:
Cream the butter and sugar together until pale, smooth, and soft. Add the eggs one by one and mix until well incorporated.
Add the ground almonds and almond extract and beat together until well combined.
Spread the frangipane on top of the jam and smooth the top using a palette knife or the back of a spoon. Bake for 40-45 minutes until the frangipane is puffed and a deep golden brown.
Remove the Bakewell from the oven and leave to cool completely in the tin, for at least one hour.
For the Icing:
Put the water, golden syrup, and butter in a small saucepan over a medium heat and bring to a simmer.
Meanwhile, sift the icing sugar into a large bowl. When the liquid has reached a simmer and all of the butter has melted, pour onto the icing sugar, whisking well until smooth. Put 3tbsp of the mix into a small bowl and add a drop or two of the food colouring to make a pink icing.
Moving quickly, pour the white icing over the top of the Bakewell, smooth the top, then spoon lines of the pink icing on top. Drag a skewer through the lines to feather the icing.
Leave to set completely, for at least three hours at room temperature before cutting into slices to serve.