Blend butter and cream cheese together until light and fluffy, add in the flour and mix until the dough comes together. Place the dough in cling film and chill for 60 minutes.
Preheat oven to 200°C/180°C fan/gas 6 and line a tray with baking paper. On an icing sugared surface, knead the dough for a few minutes and create a ball.
Roll the dough into a circle with a rolling pin, about 2.5mm thick.
Using a 10cm biscuit cutter, cut the dough into rounds and place on the baking paper.
Fill each pie round with 1tsp of Rhubarb & Stem Ginger Jam. Take one side of the dough and pull it over the filling. Use a fork to crimp the edges together and poke an air hole at the top of the pie. Brush each pie with egg wash and sprinkle with caster sugar.
Bake for 20-25 minutes, turn over half way though, until golden, then cool on a wire tray
Sprinkle with icing sugar, serve with whipped cream or ice cream.