Step 1: The Crucial Pumpkin Blot
Spread your ½ cup of pumpkin puree onto a large plate lined with three layers of thick paper towels. Top it with another two layers of paper towels and press down firmly to absorb the liquid. Repeat this process 2 to 3 times until the puree reduces in volume by almost half and resembles a thick, concentrated paste. This concentrates the flavor and eliminates the water that causes cakey dough.Step 2: Mixing the Wet Ingredients
In a large mixing bowl, aggressively whisk the melted butter, dark brown sugar, and granulated sugar together until no lumps remain. Add your concentrated, blotted pumpkin paste, the room-temperature egg yolk, and the vanilla extract. Whisk for about 60 seconds until the mixture is completely smooth, glossy, and emulsified.Step 3: Whisking the Dry Spices
In a separate medium bowl, whisk together the all-purpose flour, baking soda, sea salt, cinnamon, ginger, nutmeg, and cloves. Whisking for at least 30 seconds ensures the powerful spices are evenly distributed, preventing any overwhelming bites of pure clove later on.Step 4: Combining and Folding
Pour your dry spiced mixture into the wet pumpkin mixture. Using a rubber spatula, gently fold the ingredients together just until the last streak of white flour disappears. Overmixing at this stage activates the gluten strands, which will result in tough cookies.Step 5: Chilling the Spiced Dough
Cover the bowl tightly with plastic wrap and chill the dough in the refrigerator for exactly 30 minutes. Because we used melted butter, the fat needs to re-solidify. If you skip this, your cookies will melt into paper-thin, greasy discs in the oven.Step 6: Baking to Chewy Perfection
Preheat your oven to 350°F (175°C) and line your baking sheets. Scoop 1.5-tablespoon balls of dough, space them 2 inches apart, and bake for 10-12 minutes. The edges should look set, but the centers will appear slightly underbaked and gooey. Pull them out and let them carry-over cook on the hot baking sheet for 5 minutes before moving them to a cooling rack.