Preheat oven to 350℉.
Grease 12-cup Bundt pan. I like to use Baker's Joy for best results.
Whisk flour, baking soda, baking powder, salt, cinnamon, cardamom, allspice, and black pepper in a medium bowl. Set aside.
3 cups Unbleached All Purpose Flour, 2 tsp Baking Powder, 1 tsp Baking Soda, 1¼ tsp Kosher Salt, 2 tsp Ground Cinnamon, 1½ tsp Ground Cardamom, ½ tsp Allspice, ¼ tsp Black Pepper
Using the stand mixer (with paddle attachment), combine brown sugar, butter, and olive oil. Beat on med-high until light and fluffy (about 3 minutes).
2 cups Dark Brown Sugar, ½ cup Unsalted Butter, ½ cup Extra Virgin Olive Oil
Add eggs, 1 at a time, mixing for 20 seconds between each egg until well incorporated into cake batter.
2 Large Eggs
Add pumpkin puree and sour cream. Mix until well combined. Scrape sides and bottom of bowl as necessary.
½ cup Sour Cream, 1 can Pureed Pumpkin
Add dry ingredients and mix.
Pour batter into Bundt pan, smooth the top with a spatula, and firmly tap the pan on the countertop a few times to release any large air bubbles.
Bake cake until golden and puffed, about 60 minutes. When checking doneness, listen for bubbling. I used an internal thermometer to check doneness, and pulled the cake from the oven when it read 200℉. Anywhere between 200-210℉ is ideal.
Set cake, still in pan, on a cooling rack for 20 minutes. Then release the cake out the Bundt pan to finish cooling before glazing. If you try to glaze too soon, it will all melt off.