Preheat the oven to 325 degrees F. Line a regular-size cupcake pan with 18 cupcake liners.
In the bowl of an electric stand mixer with a paddle attachment, mix the dry ingredients on slow speed until fully incorporated. Slowly add the oil and eggs to the bowl. Add the buttermilk, molasses, applesauce, and pureed ginger, and then mix on medium speed for 1 minute. Stop and scrape the bowl and paddle, and then mix on medium speed for 2 minutes.
Fill the cupcake liners three-quarters full with batter and bake until baked through, about 20 minutes. Do not open the oven during this time. Cool the cupcakes completely after baking.
Put the Zinfandel Buttercream Frosting into a pastry bag and cut 1/2-inch off the tip. Frost each cupcake in a circular motion until the top of the cupcake is completely covered and serve.
Pour the zinfandel into a saucepan and cook over medium-high heat until the liquid comes to a boil. Reduce the heat to low and stir constantly until reduced by half. Take off the stove and cool in the refrigerator until cold.
In the bowl of an electric stand mixer with a whisk attachment, whip the butter until creamed. Add the powdered sugar and zinfandel reduction and mix until the ingredients are evenly incorporated and the frosting is smooth and creamy.