Dry the pumpkin puree: Press canned pumpkin puree between paper towels until most of the liquid is absorbed, about 1 minute. It should feel thick and paste-like, not watery.

Cream butter and sugar: Beat softened butter and brown sugar together until pale and fluffy, about 2 minutes. This builds air into the dough so the cookies stay soft.

Add egg and pumpkin: Beat in the egg, vanilla extract, and dried pumpkin puree until the mixture looks smooth and uniform in color.

Mix dry ingredients: Stir together flour, baking soda, salt, and pumpkin pie spice in a separate bowl so the spice spreads evenly through the dough.

Combine wet and dry: Fold the dry ingredients into the wet mixture just until no streaks of flour remain. The dough should feel soft but hold its shape when scooped.

Chill if needed: If the dough feels sticky, chill it for 15 minutes; this keeps the cookies from spreading too thin in the oven.

Preheat and scoop: Preheat the oven to 350°F and line a baking sheet with parchment paper. Scoop rounded tablespoons of dough 2 inches apart.

Bake the cookies: Bake for 10-12 minutes, until the edges turn matte and set while the centers still look soft. They firm up as they cool on the tray.

Cool completely: Let the cookies rest on the tray for 5 minutes, then move them to a wire rack. Cool fully before icing, about 20 minutes, so the icing doesn't melt.

Mix the icing: Whisk powdered sugar with milk, one tablespoon at a time, until the icing is thick but pourable from a spoon. Split it into two bowls and tint one green and one purple with gel food coloring.

Swirl the colors: Drop small spoonfuls of green and purple icing side by side on each cooled cookie. Drag a toothpick through both colors once or twice to create a marbled swirl.

Let icing set: Let the iced cookies sit at room temperature for 15-20 minutes until the icing firms up before stacking or serving.