Preheat the oven to 400°F (204°C). Place a rack in the lower third of the oven. Line 1 or 2 large baking sheets with parchment paper or silicone baking mats. If you're making mini scones, use 2 baking sheets. Set aside.

Whisk the flour, baking powder, cinnamon, pumpkin pie spice, and salt together in a large bowl. Grate the frozen butter on the large holes of a box grater. Add the grated butter to the flour mixture and cut it in using a pastry blender, two forks, or your fingertips until the mixture forms pea-sized crumbs. Set aside.

In a small bowl, whisk together 1/3 cup of the heavy cream, the egg, blotted pumpkin, brown sugar, and vanilla extract. Drizzle the liquid over the flour-butter mixture and stir until everything is just moistened.

Flour your hands and gently work the dough into a ball as best you can. Turn it out onto a lightly floured surface and press into a neat 8-inch disc. With a very sharp knife, cut into 8 equal wedges. For smaller scones, press the dough into two 5-inch discs and cut each into 8 wedges.

Place the scones at least 2 inches apart on the prepared pans. Using a pastry brush, brush the tops with the remaining heavy cream and sprinkle with coarse sugar if desired for a crunchy sparkle.

Bake the larger scones for 20-25 minutes, until lightly browned. If baking mini scones, check at 18-20 minutes. Let them cool for a few minutes on the baking sheet while you make the glaze.

In a small saucepan over low heat, melt the butter and maple syrup together, whisking occasionally. Once the butter is melted, remove from the heat and whisk in the sifted confectioners' sugar. Add a pinch of salt if you like. Drizzle the glaze over the warm scones.

Serve immediately; leftovers keep at room temperature or in the refrigerator for up to 2 days.