Take the short pastry out of the fridge and unwrap the dough. Roll it out into a thin sheet, 0.5/2” thick. Cover the bottom of the cake pan and put a margin around as the filling will get around 4 cm/1.4” high.
Now pick the bottom with a fork, fill in the apple sauce and cover all with another sheet of dough. You don’t need to ‘fix’ it really well, it will not open during baking time.