Add the flour, xanthan gum, salt and sugar to a large mixing bowl and stir together.

Cut the COLD butter into cubes and then add to the bowl. Using your fingers, rub the mix together until it resembles breadcrumbs.

Crack the eggs into a bowl or mug and add the cold water. Whisk together until just combined. Then add to the mix and use a fork to start to ‘mush’ the mixture together. You’ll see it start to form a sticky dough.

Once it becomes harder to use the fork to mix, use your hands to bring the mixture together into a smooth dough. You should be able to pick this up easily without it being too sticky.

Wrap the dough in clingfilm and chill in the fridge for at least 30 minutes. This is a really important stage – you need the dough to chill a bit so it is easier to roll!

Once you're ready to roll the dough, preheat the oven to 180'C / Fan 160'C / Gas Mark 6. Line a baking tray with baking paper.

Roll the dough (either on a well-floured worktop or between two sheets of clingfilm) to around 3-4mm thick. Then use a ruler or straight edge to cut our four rectangles, measuring approximately 7cm by 10cm (3x4inches) each.

Lay half of the rectangles out on the baking tray. Spread around 1 tbsp of jam in the centre of half of each one, leaving at least half an inch around the edges.

Brush the edges of the pastry with the beaten egg around the jam – this is important as it will help seal the pop tarts and ensure the jam doesn’t leak out!

Prick the other rectangles with a fork. This will allow any steam to escape as they bake and again, stop your pop tarts exploding in the oven. Lay the pricked-pastry rectangles on top of the jammy ones and seal the edges with your fingers. Then use a fork to press the edges down together, before egg-washing all over.

Bake the pop tarts in the oven for 20-22 minutes, until golden brown on top. Remove from the oven and leave to cool completely.

Mix the icing sugar and water to form a thick paste. Smooth the icing onto the cooled pop tarts and then decorate with sprinkles.