In a large bowl, whisk together the almond flour, powdered erythritol, and salt.
Add the cold cubed butter, vanilla extract, and almond extract. Use a pastry cutter or your fingers to work the butter into the flour mixture until it forms a cohesive dough that holds together when pressed. It will be crumbly at first but will come together.
Turn the dough out onto a sheet of plastic wrap. Shape it into a log about 2 inches in diameter. Wrap tightly and refrigerate for at least 1 hour until firm.
Preheat oven to 325°F (165°C). Line a baking sheet with parchment paper. Slice the chilled dough log into rounds about 1/3 inch thick and place them on the baking sheet, spacing about 1 inch apart.
Bake for 14 to 17 minutes, until the edges are just turning golden. The centers will still look soft.
Let the cookies cool completely on the baking sheet. They are very delicate when warm and will firm up into perfectly buttery, crumbly shortbread as they cool. Handle them only after they reach room temperature.
