Make a well in the middle of the flour mixture and add the egg.
Gently stir the egg with a fork/spoon and take the flour mixture from the sides to incorporate.
Stop when the mixture forms clusters. Make a ball out of the dough.
Place the dough onto a plastic film and make a disc.
Cover with plastic film and keep in the fridge for 1 hour or in the freezer for almost 15 minutes.
Put the apple slices into a large mixing bowl and stir in the lemon juice. Add in the cinnamon, nutmeg, sugar and flour.