In a large bowl or base of a stand mixer, stir together almond flour, 1 1/2 cups all purpose flour, cornstarch, oats, salt, baking powder, pumpkin pie spice, and cinnamon.
Next, add pumpkin puree, honey, vanilla, butter, eggs, and 1/4 cup buttermilk. Beat on medium-high speed until well combined, about 2 minutes.
The dough will be very sticky, but the best you can, form it into a large ball and cover with plastic wrap. Place ball of dough in refrigerator for at least 2 hours.
After dough has chilled, use ~2 tbsp of all purpose flour to coat a surface when you can roll out the dough. Place dough on floured surface and sprinkle a small amount of flour over top of dough. Roll until ~1/8 inch thickness. Cut dough into 4 inch by 4 inch squares (will make about 12 squares, if you can't get all the squares cut out of first roll out of the dough, make another ball with remaining dough and roll this out).