In a small sauce pan, add 1 cup of pumpkin puree, and keep over low heat to remove some of its moisture, about 20 minutes. Reserve to a bowl and place in the refrigerator until ready to use.
In a large bowl whisk together the flour, baking powder, salt, cinnamon, nutmeg, ginger, cloves, and allspice.
Add butter, sugar, and 2 tablespoons pumpkin puree to a stand mixer, and beat until light, fluffy, and pale about 2-4 minutes.
Add the low-moisture pumpkin and sour cream, mixing until everything is fully incorporated, but not longer.
Add the flour mixture in batches, making sure everything is incorporated before adding the next addition. I do this in about 4 additions.
Line a large bowl with plastic wrap, and place the dough inside, folding the plastic wrap up and over the dough. Refrigerate for at least 30 minutes. In the mean time, make your glaze.
In a medium bowl, add the glaze ingredients together. Whisk until no lumps remain. Set aside.