Grease a tart tin with 1 teaspoon of butter, if desired, or line it with baking paper.

For the shortcrust pastry, place the flour and salt in a bowl. Add the cold butter and rub it into the flour by hand until the mixture resembles fine breadcrumbs. Pour in the water and quickly bring everything together to form a soft, smooth dough.

Roll out the dough to the size of the tin and place in the fridge.

For the topping, halve the plums and remove the stones.

Prick the dough several times with a fork. Mix the ground hazelnuts with the cinnamon and spread over the base of the pastry. Now arrange the plum halves on top.

For the filling, halve the vanilla pod and scrape out the seeds. Place the vanilla seeds in a tall bowl together with the egg, cream alternative, cornflour, soya drink and sugar, and whisk or blend until combined. Pour the topping over the plums.

Bake the tart in the oven at 180 degrees (top and bottom heat) for about 30 minutes.