Preheat the oven to 350°F (175°C) and grease the baking pan.

In a mixing bowl, combine the pumpkin puree, granulated sugar, brown sugar, melted butter, eggs, and vanilla extract. Whisk until smooth.

In another bowl, whisk together the flour, cocoa powder, baking powder, salt, cinnamon, nutmeg, and ginger.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Pour the batter into the prepared baking pan and spread it evenly.

Bake for 25-30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.

Allow to cool in the pan before cutting into squares.