Preheat oven to 375 °F and lined baking sheet with parchment paper or a silicone mat. Set aside.
Combine flour, baking powder, salt, pumpkin spice, and mix in a large mixing bowl. Grate the frozen butter directly into the flour mixture and combine with a fork or your fingers. The mixture should resemble breadcrumbs with pea-size crumbs.
Whisk egg, buttermilk, pumpkin puree, sugar, and vanilla extract together in a medium mixing bowl. Pour the wet ingredients or pumpkin mixture into the dry or flour ingredients and gently mix to combine. Transfer dough onto a floured board and form it into 8 inches disc using your fingers. Put the dough into the refrigerator to firm up for about 10 minutes. Use a bench scraper or sharp knife to cut into 8 wedges.
Brush the scones with cream (or buttermilk or egg wash) and sprinkle with coarse sugar. Transfer the scones onto the prepared baking sheet and bake in a preheated oven for 18- 22minutes or until golden brown.
Remove from oven and allow to cool.
Prepare Glaze for Pumpkin Scones
Mix the cream and powdered sugar until well combined. Drizzle on cooled scones before serving.