Preheat the oven to 3250F and line a large baking sheet with parchment or a silicone liner.

In a large bowl, whisk together the almond flour, erythritol sweetener, pumpkin pie spice, baking powder, and salt. Stir in the pumpkin puree, egg, melted butter, and vanilla extract until the dough comes together.

Turn the dough out onto the prepared baking sheet and pat into a low log about 4 by 10 inches. Bake about 25 minutes, until the log is just firm to the touch.

Remove and let cool 15 minutes, then gently slice into 12 even slices using a serrated knife. Reheat the oven to 2500F.

Place the slices back onto the baking sheet, cut-side down, and bake for 15 minutes. Flip each slice carefully and continue to bake for another 15 minutes. Turn off the oven and let them sit inside until cool. Keep your eye on them in case they brown too quickly. They will firm up as they cool.

For the glaze, whisk together the powdered sweetener, vanilla extract and enough liquid (e.g., water or almond milk) to make the glaze of a drizzling consistency. Drizzle over cooled biscotti.