Let the butter reach room temperature to be easier to work with. Mix butter with sugar. Add egg and baking powder and mix until smooth. Stir down the flour and mix to a dough. Put the dough in the fridge for 30-60 minutes (optional but makes it easier to roll).

Divide the dough into 3 balls. Then roll them out the size of the oven tray. Add extra flour if too sticky. Make a “groove” in the middle and fill it with jam. Bake for 15 minutes in 175ºC.

Let cool off just a couple of minutes. They need to still be warm when you add the topping.

Mix icing sugar with water and spread on top of the jam. Let set and then cut in diagonal while still a bit warm. Freezes well but need grease proof paper between the layers to keep them from stick to each other.