Preheat your oven to 350°F and line a cupcake pan with paper liners.
Combine the all purpose flour, baking soda, ground cinnamon, ground ginger, ground nutmeg, ground allspice, and salt in a medium bowl. Stir well.
In the bowl of an electric mixer, beat the butter and dark brown sugar until blended.
Add the egg, then the molasses and blend until combined.
Slowly add the milk and then gradually add the flour mixture until evenly blended, scraping down the side of the bowl as necessary.
Fill the cupcake pan wells ⅔rds of the way full.
Bake for 18-20 minutes, or until the cupcakes spring back to touch. You can also use a toothpick in the center of one to make sure it comes out clean.
Let cool.
Add the butter to the bowl of an electric mixer and beat until somewhat whipped.
Mix in the cinnamon and vanilla extract and until evenly incorporated.
Very gradually add the powdered sugar until it’s fully blended and smooth.
Apply the Cinnamon Vanilla Buttercream Frosting to the cooled Gingerbread Cupcakes with a butter knife, small spatula, or a piping bag and tip.
