Cut the nectarines into medium-sized cubes of about 1 cm, transfer to a medium bowl, add sugar, flour, salt and lemon juice and mix well.
Remove the pan with the dough from the refrigerator, spread the bottom with almond butter, and place evenly the nectarine filling on top.
Remove the second dough ball from the refrigerator; Roll it out between two baking sheets to create a circle about 25 cm in diameter (the diameter of the top of the pie pan); remove one baking sheet, flip so that the side without the paper is facing down, and place in the pan, on the filling. Remove the other baking paper. Close the dough around - while pushing it with the sides down.
Using a knife, make 4-6 cuts in the center of the dough, to allow the steam to be released - without harming the top dough.
Bake in the center of the oven - 45-50 minutes - or until nicely golden. Remove from the oven and cool on a wire rack.
Sprinkle with powdered sugar (preferably ground with vanilla). Serve lukewarm or at room temperature.
Serve with vegan vanilla ice cream.