Line a large cookie sheet with parchment paper. Set aside.
In a large bowl, whisk together the flour, sugar, baking powder, pumpkin pie spice and salt.
Add the cold diced butter and using your fingertips, rub the butter into the flour mixture until it resembles coarse crumbs.
In a separate small bowl, whisk with heavy cream, pure pumpkin, and vanilla extract until combined.
Create a small well in the center of the flour mixture. Pour the pumpkin mixture into the well and stir with a fork until the dough comes together.
Turn the dough out onto a lightly floured surface. Fold dough in half over itself and gently flatten. Rotate the dough 90 degrees and fold it over itself and flatten it again. Repeat this step 2 - 3 more times, taking care not to overwork the dough. Then, form the dough out into a 3/4-inch-thick round. Cut into 8 wedges. For best texture and highest rise, place the scones in the freezer for 15-30 minutes.
While the scones are chilling, preheat the oven to 350º F (180º C).
Brush the scones with heavy cream and bake for about 18 to 20 minutes or until risen, set in the centers, and slightly golden on the bottoms.
Remove from oven and allow to cool down completely on a wire rack.