Put the butter, sugar, flour and almonds into a food processor and whizz until the mixture just comes together and forms a ball. If making by hand, first beat together the butter and sugar, then add the flour and ground almonds. Wrap in cling film and leave in the fridge for at least 1 hr.
Remove the dough from the fridge and knead until it is soft enough to shape and roll. Divide into two even-size balls. Sprinkle a little plain flour over your work surface and roll out one ball of pastry. I find it best to start the rolling myself so that it’s even, then let the kids finish it off. The dough should be approximately 5mm thick. Using a star cutter (about 6cm wide) dipped in a little flour to stop it from sticking, cut out as many star shapes as you can. Then lightly knead the dough trimmings together and roll out again. Keep going until you have about 24 stars. Carefully place the stars on a baking sheet, making sure you keep them slightly apart.
Roll out the second ball of dough the same way. Cut out the same-size stars and place them on a baking sheet. Now cut out a small circle in the centre of each biscuit using a small cookie cutter or the end of a large piping nozzle.
Heat oven to 140C/fan 120C/gas 1 and cook the biscuits for 20-30 mins until just golden. Remove from the oven and place on a cooling rack to cool completely. Place a blob of jam onto the centre of the biscuits without the cut-out circle. Be generous – you want the jam to show at the edges as well as the centre. Place the top halves of the biscuits on and push down gently. These will keep in an airtight container for up to 3 days.