In a large mixing bowl, whisk together all-purpose flour, baking powder, fine sea salt, baking soda, and spices until well combined.

Cut cold cubed butter into the flour mixture until it resembles coarse crumbs.

In a separate measuring cup, combine pumpkin puree, buttermilk, and egg, whisking until smooth.

Create a well in the center of the dry ingredients and pour in the wet mixture, stirring gently until just combined.

Transfer the dough to a floured surface and pat into a rectangle about 1 inch thick, folding it into thirds.

Cut the dough in half and form each half into a 6-inch round, slicing each round into 6 wedges.

Preheat the oven to 400°F (200°C) and brush unbaked scones with egg wash.

Bake for 15–18 minutes until puffed and golden brown.

While cooling, whisk together powdered sugar, milk, and ground cinnamon for the glaze.

Drizzle the glaze over the cooled scones and serve.