Spread the measured pumpkin on folded paper towels, press with more towels, and repeat until it looks thick rather than glossy or watery.
Whisk melted butter with both sugars until smooth, then whisk in the blotted pumpkin, egg yolk and vanilla.
Whisk flour, cinnamon, baking soda, ginger and salt separately. Fold the dry mixture into the wet ingredients just until no flour streaks remain; fold in pecans if using.
Cover and chill the dough for 30 minutes. Meanwhile, heat the oven to 350°F and line two sheet pans with parchment.
Scoop level 1 1/2-tablespoon portions 2 inches apart. Bake one pan at a time for 10 to 13 minutes, until the edges are set and the centers look matte but still soft.
Cool on the pan for 5 minutes, then move to a rack. Whisk the glaze ingredients to a thick drizzle and add only after the cookies are completely cool.
