Preheat oven to 400°F (200°C).

Mix almond flour, confectioners' sugar, and salt until well combined.

Add unsalted butter and mix until the mixture resembles coarse crumbs.

Roll out the mixture into a large rectangle, about 1/4-inch thick.

Fold the rectangle in half lengthwise, like a letter.

Rotate the dough 90 degrees, so the folded edge is facing you.

Roll out the dough again into a large rectangle, about 1/4-inch thick.

Cut into long, thin triangles.

Roll each triangle into a croissant shape, curving the dough into a crescent.

Place the croissants on a baking sheet lined with parchment paper, leaving about 1 inch of space between each.

Brush the tops with egg wash (beaten egg mixed with a little water).

Bake for 15-20 minutes, or until golden brown.

Allow the croissants to cool on a wire rack for 10-15 minutes before serving.