Gluten-Free Whoopie Pies with Pumpkin Buttercream Filling
These irresistible and pillowy gluten-free whoopie pies are made with two moist chocolate cake mounds and a fluffy pumpkin buttercream frosting center.
Preheat your oven to at 375º F and line 2 baking sheets with parchment paper. Set them aside.
Combine the milk with 1 tablespoon of lemon juice in a small bowl and allow the mixture to sit for 5 minutes. Then add 1 large egg to the milk mixture and whisk everything together with a fork.
Using a standing or handheld mixer, beat the butter with the sugar until the mixture is light and fluffy.
In a separate bowl, lightly whisk together the flour, cacao powder, baking soda, and baking powder.
Alternate adding the milk mixture and the flour mixture to the creamed butter and sugar, mixing everything together between additions until all the ingredients are incorporated.
Add the hot water and beat the batter until smooth.
Using an ice cream or cookie scoop, place 24 even mounds of the cake batter onto parchment paper-lined baking sheets, then bake the cookies for 10-12 minutes until they're firm and lightly spring back when touched. Allow the cookies to cool for 5 minutes on the baking sheet before transferring them to a cooling rack.
Once they're cooled completely, prepare the buttercream in your standing or handheld mixer. Beat together the butter, pumpkin puree, pumpkin pie spice, and vanilla extract. Mix together 1 cup of powdered sugar at a time until all the powdered sugar is incorporated. Beat the mixture until the frosting is light and fluffy, about 1-2 minutes. You can add up to 1/2 cup more powdered sugar for a thicker frosting.
Pipe the buttercream frosting onto the flat side of half of the cookie mounds, then place a second cookie mound on top to form sandwich cookies.
Notes
Recipe for a simple vanilla buttercream (vs. pumpkin buttercream):
1/3 cup softened butter
3 cups powdered sugar
1 tsp vanilla extract
1-2 tbsp milk, as needed
How do you get the cakes to be evenly sized? You want the cookies to be as evenly sized as possible. Be sure to use a medium-sized cookie scoop or ice cream scoop to form your mounds.Can I make them dairy free? You can try using plant-based milk (choose something rich and creamy like cashew milk) and plant-based butter; however, the texture may not be the same.Can I make them egg free? I have not tried making them egg free, but if you do, I suggest trying this egg substitute.Can I use a different gluten-free flour blend? I've only tested this recipe with Bob's Red Mill 1-to-1 Gluten-Free Flour, but you could try making it with another flour blend. If you do, choose a 1-to-1 or cup-for-cup blend with xanthan gum or add 1 1/2 tsp of xanthan gum.