Place the almond flour, salt, and coconut sugar in a food processor and pulse to combine.
Add the cubed cold butter and pulse until combined and the dough resembles wet sand.
Add the vodka or cold water 1 tablespoon at a time, pulsing the dough until it resembles a ball of dough.
Remove the dough from the food processor and form the dough into a disk. Wrap in plastic wrap and refrigerate for 30 - 60 minutes.
Prepare the filling by combining the sliced peaches and blueberries in a medium bowl.
Toss the peaches and blueberries with corn starch, then drizzle with honey and stir to coat.
Roll out the dough onto a Silpat or sheet of parchment paper. It may break slightly, but you can use your fingers to shape it.
Transfer the parchment or Silpat to a baking sheet.
Place the peaches and blueberries in the center of the galette, leaving 2 inches of crust around the edges.
Fold the edges of the dough over the filling, then brush with the beaten egg.
Gently place the sliced almonds around the crust.
Bake for 25 to 30 minutes until the crust and almonds are browned.
Cool slightly (about 5-10 minutes) before serving. Enjoy with your favorite ice cream or whipped cream if desired.