Preheat oven to 425 degrees F. Lightly oil a baking sheet or line with parchment paper. Combine flour, sugar, baking powder, salt, and spices in a large bowl. Using a pastry knife, fork, or food processor, cut butter into the dry ingredients until mixture is crumbly and no chunks of butter are obvious. Set aside.
In a separate bowl, whisk together pumpkin, half and half, and egg. Fold wet ingredients into dry ingredients. Form the dough into a ball.
Pat out dough onto a lightly floured surface and form it into a 1-inch thick rectangle (about 9 inches long and 3 inches wide). Use a large knife or a pizza cutter to slice the dough twice through the width, making three equal portions. Cut those three slices diagonally so that you have 6 triangular slices of dough. Place on prepared baking sheet.
Bake for 14-16 minutes. Scones should begin to turn light brown. Place on wire rack to cool.
TO MAKE THE PLAIN GLAZE:.
Mix the powdered sugar and 2 tbsp milk together until smooth.
When scones are cool, use a brush to paint plain glaze over the top of each scone.
AS THAT WHITE GLAZE FIRMS UP, MAKE THE SPICED ICING:
Combine the ingredient for the spiced icing together. Drizzle this thicker icing over each scone and allow the icing to dry before serving (at least 1 hour). A squirt bottle works great for this, or you can drizzle with a whisk.