In a large bowl, mix the egg, heavy cream, pumpkin puree, brown sugar, and vanilla together. Set it aside.
Add the flour, baking powder, salt, pumpkin spice and butter to a food processor. Pulse until the butter is incorporated into the flour. Make sure there are still small chunks of butter, no larger than the size of a pea. These butter "chunks" are what make the scones flaky.
Add the flour, baking powder, salt, pumpkin spice and butter to a food processor. Pulse until the butter is incorporated into the flour. Make sure there are still small chunks of butter, no larger than the size of a pea. These butter "chunks" are what make the scones flaky.
Put the dough on a lightly floured surface, and shape it into an 8" circle. Then, cut the dough into 8 pieces.
Place the triangles onto a large baking sheet lined with parchment paper. Make sure to leave at least an inch between each triangle. Place the baking sheet in the refrigerator for 30 minutes. While the scones are chilling, preheat the oven to 400º F.
Remove the scones from the fridge, and brush the tops with cream. Then, bake the scones for 20-25 minutes, until the edges are lightly browned.
While the scones are baking, you can prepare the brown sugar glaze. Heat the butter, milk and brown sugar in a small pot. Simmer on low for about 2 minutes, while stirring, until the sugar is dissolved. Remove from the heat and let it cool for a few minutes. Then, whisk in the powdered sugar, a little at a time, until you reach your desired consistency.
Let the scones cool on the baking sheet for a few minutes. While they're sill warm, drizzle the glaze over them. Enjoy!