Preheat your oven to 350°F (175°C) and line a couple of baking sheets with parchment paper. Easy cleanup, always a win.
In a large mixing bowl, cream together the butter and both sugars until the mixture is light and fluffy — about 2–3 minutes of mixing.
Beat in the egg, vanilla, and pumpkin until the batter is smooth.
Dissolve the espresso powder in 1 teaspoon of warm water (this helps it mix in evenly), then stir it into the batter.
In a separate bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg, and salt.
Slowly add the dry ingredients into the wet mixture, stirring just until combined. The dough will be soft and sticky — that’s exactly what you want.
Scoop out big mounds of dough (about 3 tablespoons each) and drop them onto the prepared sheets, spacing them about 2 inches apart.
Bake for 12–14 minutes, or until the cookies are puffed and the edges are set.
Transfer to a wire rack and let them cool completely before frosting.