Preheat oven to 375°F. Line a baking sheet with parchment paper.

In a food processor, blend coconut flour, hazelnuts, potato starch, chia seeds, baking powder, salt, and stevia (if using liquid, add it to the liquid ingredients) until the mixture is powdered.

Add remaining ingredients and process just until blended and uniformly moist (do not overmix). Gently turn the mixture onto the baking sheet. Wet your palms and shape the dough into a flat log, roughly 8 inches long and ½ - ¾ inch high (make it higher if you prefer thicker biscotti). Using a sharp knife, cut across the log diagonally to create about a dozen pieces, about ¾-inch thick.

Gently move the biscotti apart so there is space between pieces. Bake for 20 minutes, until the edges just begin to brown. Remove from the oven and turn each piece over.

Reduce heat to 350°F and bake for another 25 minutes. Turn off heat and leave the biscotti in the oven until completely cool, about an hour. They should be lightly browned and very crisp. Store, covered, at room temperature for up to 4 days. May be frozen.