Prepare the filling: Sauté apples, butter, sugar, and water in a pan until soft. Remove from heat and stir in cinnamon & walnuts. Let it cool.
Make the dough: Mix all ingredients except flour. Gradually add flour until a smooth dough forms.
Roll it out on parchment paper, cut excess edges, and chill the scraps in the freezer.
Shape the tart: Add the apple filling to the center, create decorative edges, and grate the chilled dough on top.
Bake at 180°C (350°F) for 25-30 minutes until golden.
Cool slightly, dust with powdered sugar, and enjoy!
