In a large mixing bowl, whisk the coconut sugar, pumpkin puree, melted butter, and applesauce until smooth. Beat in the egg and vanilla until fully incorporated.

Stir the rolled oats, baking soda, pumpkin pie spice, and salt into the wet mixture. Gently fold in the whole wheat pastry flour, mixing just until no dry streaks remain.

Cover the bowl with plastic wrap and chill for 1 hour. Meanwhile, preheat your oven to 350°F and line a large sheet pan with parchment paper.

Once chilled, scoop the dough into 12 equal mounds, using about 1/4 cup per cookie. Gently press each mound down with your palm, then bake for 14 to 16 minutes, or until the edges are set.

Let the cookies cool completely on the pan. To make the glaze, whisk the powdered sugar with 1 tablespoon of milk until smooth. If it's too thick, add another 1/2 tablespoon of milk at a time until the glaze is pourable.

Drizzle the glaze over the fully cooled cookies, letting it cascade down the sides. Allow the glaze to set for at least 1 hour before serving so it firms up.