Mix the diced butter and sugar in a stand for about 2 minutes; then add the egg;
When combined well, add the flour, the baking powder, and the salt;
Switch off the stand mixer, put the mixture onto a pastry board, and shape it quickly into a compact ball;
With a rolling pin, roll out the dough on a sheet of parchment paper until it’s thin enough to cover the pie pan;
Take the sides of the parchment paper and drape the dough over the pie pan;
Trim any excess dough from the rim of the pan; crimp the dough all the way around in a nice pattern;
Refrigerate the dough for 1 or 2 hours;
Take the pie crust out of the fridge and quickly prick the surface with the tines of the fork;
Evenly spread the marmalade and top with thin slices of apples;
Bake in a static oven at 325°F (163C°) for 30-35 minutes;
Make the second pie crust. Fill it with the jam (about 350g) and the apples. Make a lattice pattern to decorate it with excess dough.