Preheat the oven to 400°F (200°C).
In a large bowl, combine flour, sugar, baking powder, salt, and pumpkin pie spice.
Cut in cold butter using a pastry cutter until the mixture resembles coarse crumbs.
Mix sourdough discard, heavy cream, and vanilla in a separate bowl. Add to the dry ingredients.
Gently mix until the dough comes together. Avoid overmixing.
Transfer dough to a floured surface and shape into a 1-inch thick circle.
Cut into 8 wedges or rounds and place on a parchment-lined baking sheet.
Brush the tops with heavy cream and bake for 15–20 minutes, or until golden.
Let the scones cool completely before serving.