Preheat the oven to 425 degrees . Line a baking sheet with parchment paper; set aside.
In the bowl of a stand mixer fitted with paddle attachment, stir together the flour, sugar, baking powder, salt, cinnamon, nutmeg, cloves and ginger. Add the butter and toss with a fork to coat with the flour mixture. Mix on medium-low speed until the texture resembles coarse cornmeal, with the butter pieces no larger than small peas.
In a separate bowl, whisk together the pumpkin, half-and-half and egg. Fold wet ingredients into dry ingredients, and form the dough into a ball
Pat out dough onto a lightly floured surface and form into a 1-inch thick rectangle about 4 inches by 12 inches. Use a large knife to slice the dough making three equal portions. Cut each of the portions in an X pattern (four pieces) so you end up with 12 triangular slices of dough.
Place on prepared baking sheet. Bake for 14-16 minutes, or until light brown. Place on wire rack to cool.
SPICED GLAZE: In a small bowl, whisk all the ingredients together, until smooth.
When scones are cool, use a pastry brush to spread the glaze over the top of each scone. Allow the icing to set before serving, about 1 hour. Serve at room temperature or re-heat in the microwave for about 10 seconds.