Preheat your oven to 375 degrees F and spray a 9x13 inch baking dish with a non-stick spray. Line the dish with parchment paper, leaving enough overhang so that it pulls out easily when the brownies have baked. Spray the parchment paper with non-stick spray and dust with flour. Set aside.
In a large bowl, whisk together the cocoa, flour, ginger, pumpkin pie spice, baking soda, cloves and salt. Set aside.
In another large bowl, whisk together the sugars, butter, molasses, egg, pumpkin beer and sour cream.
Add the dry ingredients to the wet and stir until just moistened. Do not overmix.
Pour the batter into your prepared baking dish. Smooth over the top.
Bake the brownies for 25-30 minutes or until a toothpick comes out clean. Remove from heat and let cool completely in the pan.
Once cooled, cover the dish and place in the refrigerator for 30 min.
Once chilled, remove the brownies from the fridge and release them from the baking dish by lifting out with the parchment paper. Cut them into squares and dust with confectioner's sugar. Serve!
The brownies will store in an airtight container for 3-4 days at room temperature. Enjoy!