Sift the flour & baking powder into a large bowl

Add the butter and rub it with your fingertips until the mixture resembles fine breadcrumbs

Stir the sugar, add the eggs and combine to form a soft, loose dough

Cut the marzipan into small cubes

Turn the mixture out on to a lightly floured work surface, roll in the cubed marzipan and shape the dough into a log shape about 3cm/1¼inches in diameter

Wrap the log in parchment paper or cling film and then in foil and chill in the refrigerator for at least 4 hours or until required (I put one of the logs in the freezer to use at a later date)

Preheat the oven to 190ºC/375ºF/Gas mark 5

Grease a large baking sheet (or a few if you're making a big batch)

Slice the dough into as many 8mm/⅜-inch slices as required

Place the slices on the greased baking sheet, spaced well apart

Return any remaining dough to the fridge for up to a week or freeze for up to 6 months

Bake in the preheated oven for 10-12 minutes or until golden brown

Leave on the baking sheet to cool slightly for 2-3 minutes before transferring to cool completely