Heat the oven to 325 degrees.
In a bowl, sift together the almond flour, Swerve, pumpkin pie spice, protein powder and xanthan gum until light and fluffy.
Beat together the cream of tartar and egg whites until medium peaks have formed.
Fold the vanilla and almond extracts to the egg whites.
Carefully fold the pumpkin puree into the egg whites.
Gently fold in the dry mixture to the egg whites until well combined.
Layer the batter in an ungreased angel food cake pan, and bake for 40 minutes, or until cooked though.
Invert the cake immediately to cool on a raised rack.
Run a knife along the edge and bottom of the cake to release it.
Turn the cake onto a serving platter, and dust with confectioners sugar substitute and cinnamon before serving.