Mary Berry's stained glass window biscuits
Preheat the oven to 180C/160C Fan/Gas 4. Line two baking sheets with baking paper.
Place the butter, flour and sugar in a food processor and pulse until it resembles breadcrumbs. Add the vanilla and beaten egg and pulse until it forms a smooth dough.
Using a rolling pin, roll out on a lightly floured work surface until the dough is about 5mm/¼in thick. Use your large cutter to cut out the shapes. Then use a small cutter to remove the middle (where the ‘glass’ will sit). If you don’t have any small cutters you can cut the middle out by hand, leaving about 1cm/½in of biscuit around the edge. Use a cocktail stick or skewer to make small holes if you want to hang them by thread or ribbon. Re-roll any scraps of dough to make more biscuits. Arrange on the prepared baking sheets and chill in the fridge for 10 minutes.
Separate the sweets into their colours and put them in plastic bags (one colour in each bag). Crush using a rolling pin until broken into fine grains. Sprinkle these grains in the middle of each biscuit in a generous layer that covers the hole. You can stick to one colour per biscuit or create a rainbow effect by mixing the colours.
Bake for about 15–18 minutes or until the biscuit is a pale golden brown and the sweets have melted. Leave to stand on the trays for about 5 minutes, or until firm enough to move. Carefully transfer to a cooling rack and leave to cool and firm up.
Don't make these too far in advance as biscuits will inevitably soften over a few days hanging on the tree.
The biscuits can be made up to 2 days ahead and kept in a sealed box. They also freeze well.