Blend the cottage cheese and pumpkin puree together in a small blender or food processor until completely smooth.
In a large bowl, beat the butter and brown sweetener until creamy. Add the pumpkin mixture, egg yolk, and vanilla, and beat until smooth.
Whisk together the almond flour, coconut flour, pumpkin pie spice, baking powder, xanthan gum, and salt. Stir into the wet mixture until a soft dough forms, then chill for 30 minutes.
Preheat the oven to 350°F and line a baking sheet with parchment paper. Scoop the dough into 1 1/2 tbsp balls and flatten each one to about 1/2 inch thick.
Bake for 14 to 16 minutes, until the edges are golden and the tops look set. Cool on the baking sheet for 15 minutes, then move to a wire rack and cool completely.
Whisk the cream cheese, powdered sweetener, cinnamon, and heavy cream until smooth and pourable. Drizzle over the cooled cookies and let set for 15 minutes.