1. Preheat oven to 200°C.
2. Mix rhubarb, sugar, cinnamon and ginger in a bowl until evenly coated.
3. Cut pastry into four rounds and place on baking tray. Pinch pastry around the edge and brush with beaten egg.
4. Place rhubarb on each tart, leaving a crust around the edge.
5. Bake for 20 minutes until pastry is puffed.
6. Spoon the Rhubarb & Gin Chutney over each tart and bake for 5 minutes until golden brown.
7. Place a dessertspoon of mascarpone on each tart, sprinkle over the pistachio nuts and serve immediately.