Wash and rhubarb stalks and cut them into big chunks without peeling.Dice the unpeeled apple into small cubes.
Prepare the tart
Lay the puff pastry into the tart mould.
Arrange the rhubarb chunks onto the bottom of the tart.
Put the diced apple onto the rhubarb. (The diced apple can fill the gaps between the rhubarb.)
Combine the flour and sugar together in a bowl and sprinkle the mixture on top of the fruit.
Whip the eggs until foamy and pour the whipped egg on top of the flour mixture. Retain a little to brush over the pastry.
Fold the edges of the dough over the rhubarb & apples and brush some of the whipped eggs over the pastry.
Bake the tart at 200°C for 35-45 minutes or until the crust is golden brown, and the rhubarb and apples are soft. Check the doneness with a wooden skewer. If the skewer comes out clean the tart is cooked.
Transfer the rhubarb tart to a serving plate and allow to cool.
Notes
You can eat the rhubarb tart at room temperature or cold.
During the baking process the juice from the rhubarb combines with the flour, sugar and whipped eggs to obtain a similar texture to a custard cream.