Combine dry ingredients. In a large mixing bowl, whisk together flour, brown sugar, baking powder, cinnamon, pumpkin pie spice and salt until evenly combined.

Cut in the butter. Add the diced butter and use a pastry cutter or two forks (or a food processor, see below) to cut the butter evenly into the dry ingredients until the mixture is crumbly and the butter forms no larger than pea-sized chunks.

Add in the wet ingredients. Add in the pumpkin purée, milk and vanilla extract.  Then use a spatula to quickly and gently stir the mixture until no dry streaks remain.  (Try to avoid over-mixing.)

Shape the scones. Turn the mixture out onto a flour-dusted surface and fold the dough over on itself a few times until it holds together and can form a ball.  (The dough will be a bit sticky, so don't worry.)  Pat the dough down flat into an 8-inch circle.  Then use a large knife or bench scraper to slice the dough into 8 equal-sized pie wedges.  (You may need to wipe off your knife between slices if the dough is sticky.)

Chill. Transfer the wedges to a parchment-covered baking sheet, spacing them at least 2 inches apart.  Then transfer the baking sheet to the freezer for 15 minutes or so while your oven heats.  Heat the oven to 425°F.

Bake. Briefly brush the top of each scone with a bit of buttermilk.  Then transfer the baking sheet to the oven and bake for 13-15 minutes or until the scones are lightly golden on top and cooked through.  Transfer to a wire baking rack to cool.

Glaze. In a small bowl, whisk together the glaze ingredients until combined.  (If the mixture seems too thin, add more powdered sugar.)  Then once the scones have cooled a bit, brush or drizzle the glaze on top of the scones.  Serve and enjoy!