Preheat oven to 425° F.
In a large mixing bowl, combine flour, baking powder, salt, sugar, and pumpkin pie spice. Mix well.
Add grated butter to the dry ingredients and mix to coat. Be sure the butter is VERY cold before adding. (I used frozen butter.)
Add pumpkin puree and milk; mix just until the dough starts to come together. Note: there will still be some flour that's not fully mixed in, and that's what you want. You'll mix it in more in the next step.
Transfer the dough to a lightly floured surface. Use your hands to gently pat the dough into a flat rectangle, adding small amounts of flour as necessary, and then fold the rectangle into thirds. (Fold both sides in toward the center.) Press it into another flat rectangle and repeat the folding process 3 more times.
Pat the dough into one final rectangle, 3/4 - 1 inch thick. Use a 2-3 inch biscuit cutter, dipped in flour, to cut 6-12 biscuits (number will vary based on thickness and size.)
Place on a rimmed baking sheet lined with parchment paper. Placing biscuits close to the edges of the pan and close together (touching) will help them rise.
Bake at 425° for 13-15 minutes, until the tops are golden brown.