Preheat oven to 425 °F (218 °C) and line a baking sheet with a silicone baking mat or parchment paper. Set aside.
In a medium bowl, whisk together pumpkin puree, half and half, and egg. Set aside.
In the bowl of a food processor, combine flour, sugar, baking powder, and pumpkin pie spice. Pulse a few times to combine.
Add the cold butter through the feed tube and pulse until well incorporated and mixture resembles cornmeal.
Add the pumpkin mixture to the food processor and pulse until just combined.
Turn the dough onto a lightly floured work surface and gently knead 4 to 5 times to bring the dough together. If the dough seems too sticky, add some more flour to it and knead it together.
Flatten the dough into a 1" thick circle then cut the dough in half then cut the halves into thirds.
Place the wedges on the prepared baking sheet and bake for 14-16 minutes, or just until they're starting to turn golden brown.
Remove from oven and place on a wire rack to cool completely.
In the meantime, make the spiced icing drizzle by combining all the ingredients in a bowl and mixing until combined.
Once the scones have cooled, drizzle the spiced icing on top and let harden for 10 minutes before serving.