1. Preheat the oven to 400℉. Line 2 large baking sheets with parchment paper and set aside.
2. Combine the flax meal and water in a small bowl, whisking to mix, and allow to rest 5-8 minutes until a gel forms.
3. In a large bowl add flour, sugar, pumpkin pie spice, baking powder, and sea salt. Whisk to combine well.
4. Using a pastry blender or 2 knives, cut chilled butter into the dry mixture until it resembles coarse crumbs.
5. Add the wet ingredients (flax mixture, pumpkin, and vanilla) to the dry mixture then stir with a large spoon until the dough forms into a ball. Pro tip: we like to work the dough into a ball with clean hands). The dough should be smooth to the touch (maybe a tad sticky). If the dough is too wet and sticky, add a little more flour and stir again.
6. Roll dough into 24 golf ball-sized pieces using lightly floured hands and a light touch. Place 8 balls on each of the 2 baking sheets.
7. Gently flatten each ball of dough so that it’s about ¼-inch thick and 2 ½-inches in diameter.
8. Place both pans in the oven and bake for 10-12 minutes or until the bottoms are lightly browned and the tops of the cookies are set – rotating the pans back to front (spin them) and top to bottom halfway through cooking time.
9. Remove from the oven and allow to cool slightly before using a spatula to carefully remove the cookies to a wire race. Cool completely before frosting.

To make the frosting:

1. Place softened butter, cream cheese, and vanilla in a medium bowl (or bowl of a stand mixer).
2. Beat until well combined. Add powdered sugar and pumpkin pie spice and continue to beat at high speed until fluffy.
3. Spread frosting on cooled cookies and dust with additional pumpkin pie spice or sprinkles.