Thaw the frozen puff pastry on the kitchen counter for 30 minutes. Then preheat oven to 350 F / 180 C.
In the meanwhile, make the peach filling. Clean the peaches and cut them in small thin slices about 1/4 inch thick. Place them in medium bowl and sprinkle with sugar, almond flour and ground cinnamon over them. Gently toss them with your hands and try to coat all peaches with the mixture.
On a large sheet of parchment paper, sprinkle 1 tbsp of flour and place the dough on the floured parchment paper. If you are using rolled out puff pastry sheets style Pepperidge Farms, simply unroll and place those two sheets on each other, so the corners creates shape of the star. This way you will be able to achieve round shape. Roll gently with rolling pin over it, to connect it. If you are using two small squared shaped puff pastry dough style Tenderflake, place them on each other and roll out round shape about 1/8 inch thick.
Start placing peach slices about 1 inch from galette edge, overlapping slightly each slice in circle, continue until you reach the centre of the galette.
Fold the outer edges of the pastry over the peaches. Tuck extra dough inside edges if it's overlapping more than 1 inch or on the other side, try to gently pull on the dough, if the edge is not thick enough. The shape doesn't need to be perfect. Brush the pastry edges with 1 beaten egg. Optional: sprinkle lightly the edges with granulated sugar.
Bake in preheated oven 350 F / 180 C for 35 - 40 minutes or until the crust is golden.Let the galette cool on the baking sheet. Cut into 8 slices, best cut with pizza cutter and serve with scoop of ice cream (optional).