Prepare your work surface by sprinkling it with flour, or use a non-stick baking mat. Roll out your puff pastry dough. If you are using shop-bought dough, it should already be rolled out. If you use homemade puff pastry, it needs to be around 3 mm thick and rolled out in a recangluar shape. Make little pricks into the pastry with a fork. (see picture)
Cut the pastry into squares (about 10 cm x 10 cm) or rectangles - whatever you fancy and place on a lined backing tray.
Wash and clean the rhubarb. Slice into 8 cm sticks. If one of your rhubarb stems is particularly thick, you can slice it in half.
Preheat the oven to 200°C or 392°F.
Prepare 1 portion of homemade German Vanilla Pudding or follow packet instructions.
Spoon the pudding on the middle of the puff pastry base on each tart. Spread but insure to leave out an approx 1 cm edge. This will allow the puff pastry to rise on the corners.
Place 3 or 4 (depending on the size of your rhubarb) chopped rhubarb sticks on the vanilla pudding base.
Place the baking tray in the oven and bake for 12-15 min until the pastry is golden and the rhubarb is cooked.
Before serving sprinkle a generous amount of icing/ confectioners sugar.