Instructions

1. In a large bowl, whisk together oat flour, coconut flour, and sea salt. Set dry ingredients aside.
2. In the bowl of a stand mixer fitted with the paddle attachment, combine coconut oil, maple syrup, and vanilla.
3. Slowly add dry ingredients to wet ingredients in three equal batches. Blend until fully incorporated and no visible signs of flour remain in the dough.
4. Allow dough to rest for 5 minutes to thicken, stirring once or twice. The dough will be soft and slightly spongy.
5. Gather up the dough and form it into a flattened disk. Wrap in plastic wrap and chill for 30 minutes to 1 hour. Note: If the dough is overchilled, it may become crumbly.
6. Preheat oven to 350F.
7. Line 2 baking sheets with parchment paper.
8. Unwrap dough and cut it into 2 equal-sized pieces. Knead each piece to warm it to the right texture (it will resemble chilled Play-Doh).
9. Lightly dust a baking area workspace with oat flour and use a rolling pin to roll 1 of the pieces of dough into a 1/4-inch-thick oval.
10. Using cookie cutters, punch out pieces of dough and carefully transfer to prepared baking sheets.  
11. Bake cookies for 12 to 14 minutes, or until just beginning to turn golden at the edges.
12. Transfer baked cookies to a wire rack to cool completely.

Prepare the vegan royal icing:

1. In the mixing bowl of a stand mixer fitted with the whisk attachment, beat aquafaba on medium speed until foamy and frothy, about 3 minutes
2. Beat in vanilla extract.
3. Add powdered sugar and mix on very low speed until fully incorporated. Then, turn mixer to high and continue beating for 5 to 7 minutes. Every few minutes, scrape down the sides of the bowl to fully incorporate the ingredients. The icing will hold a stiff peak when finished.
4. Once the cookies have cooled, place frosting in a piping bag with a tiny tip.
5. Frost each cookie by piping a line around the edges, then fill in, or “flood,” with icing. Decorate cookies with holiday sprinkles while icing is still wet. Allow icing to dry for 1 hour, or until set.
6. Serve right away or store cookies for up to 1 week.