Mix all ingredients into a firm dough. Be careful not to overwork it. Cover and let it chill in the fridge for min. 30 mins.
Crumble
Stir sugar, baking powder, salt and three tablespoons of flour together in a small bowl. Add the bits of cold butter and, using your fingertips, work them into the flour mixture until it resembles coarse crumbs. If needed add the remaining flour. Set aside.
Pre-bake crust
Generously flour your working space as well as your rolling pin. Place a to-scale cut parchment paper into your form. Gently roll out your dough then place it onto the parchment paper. With your fingers, bring the dough to an even shape allowing it to rise on the sides. Pre-back at 180° for 10 minutes.
Make the filling
Sprincle the quartered peaches with sugar and salt. Stir carefully and let them sit for 10 minutes. Spread two tablespoons of crème fraîche on the bottom of pre-baked pie, then sprikle with 1/3 of the crumble and place the peach decoratively on top. Dot the remaining crème fraîche on the peaches and sprinkle with the remaining crumble.
Bake the pie until the crème fraîche has bubbles and the crumble is golden brown - about 50 minutes. Let cool on a wire rack at least 15 minutes before serving.