In a standing mixer, mix the brown sugar (¾ cup), granulated sugar (¼ cup), and unsalted butter (¼ cup) on medium speed until well combined (about 2 minutes). Next, add the egg and mix on medium speed until completely incorporated in the batter. Scrape down the sides of the bowl halfway through to get an even mix.
Add the pumpkin puree (1 cup), greek yogurt (¼ cup), and vanilla extract (1 Tbsp) to the batter and mix on medium speed until well combined. Scrape down the sides of the bowl and continue mixing again until all of the ingredients are evenly incorporated.
In a separate bowl, whisk together the all purpose flour (1 cup), baking soda (1 tsp), ground cinnamon (1 tsp), pumpkin spice (2 tsp), and fine sea salt (½ tsp). Add the whisked dry ingredients to the pumpkin batter and stir it in with a rubber spatula. Stir until there aren't any pockets of flour left, but don't overstir. Set the batter aside.