Prepare a 13 x 9 pan or a 9 inch springform pan. Mix all the ingredients for the shortcrust pastry base in a mixing bowl and knead quickly to form a smooth dough. Shape into a disk. Place in the fridge for at least 30 minutes.
For the filling, cook the vanilla pudding. To do this, mix the milk, pudding powder ( or cornstach and vanilla), salt and sugar in a saucepan. Bring to a boil while stirring and simmer for about 1 minute. Pour the pudding into a bowl and cover with cling film. Let it cool down completely.
Meanwhile, roll out the shortcrust pastry into a rectangle and place in the lined baking pan. Press up the pastry on all sides and cut off the excess.
Now stir cooled down vanilla pudding together with the sour cream using a whisk, and pour on the shortcrust pastry in the mold and smooth it out. Top with drained cherries. Bake the cake in the oven at 160 C / 320 F circulating air in the lower third for about 60 - 70 minutes or until just set. The exact baking time depends on your oven. Leave to cool completely.
Store in the fridge and remove from the fridge about 1 hour before serving.