Preheat the oven to 350°F. Line a 12-cup muffin pan with cupcake liners. Line a second pan with 2 liners – this recipe makes about 14 cupcakes. Set aside for the time being.
Whisk together the flour, baking powder, baking soda, salt, cinnamon, cardamom and allspice in a medium bowl and set aside.
1 ½ Cups All-Purpose Flour, 1 teaspoon Baking Powder, ½ teaspoon Baking Soda, ¼ teaspoon Sea Salt, 1 teaspoon Ground Cinnamon, 1 teaspoon Ground Cardamom, ¼ teaspoon Ground Allspice
Add the brown sugar, butter, and olive oil to the bowl of your stand mixer. Using the paddle attachment, mix until light and fluffy, about 3-5 minutes. Add the room temperature egg, pumpkin puree, sweet potato puree, and sour cream one at a time. Make sure to scrape the bowl in between additions to ensure everything is well mixed.
1 cup Brown Sugar, ¼ Cup Unsalted Butter, ¼ Cup Grapeseed or Canola Oil, 1 Large Egg, ½ Cup Pumpkin Puree, ½ Cup Sweet Potato Puree, ¼ Cup Sour Cream
Add the dry ingredients in two parts, mixing until just combined.
Using a spoon or a small cookie scoop, add batter into each cupcake liner until it is halfway full. Bake the cupcakes until golden and puffed, and a tester inserted into the center comes out clean which should be about 16 minutes.
Allow cupcakes to cool completely before piping meringue on top of the cupcakes and then using a torch, lightly brown the meringue before enjoying!