Preheat oven to 350°F. Lightly grease or line 24 muffin cups with paper baking cups. Set aside. Beat cake mix, pudding mix, milk, oil, eggs, cinnamon and vanilla in bowl of electric mixer on low
speed just to moisten, scraping sides as needed. Beat on medium speed 2 minutes. Spoon batter into prepared muffin cups, filling each cup 2/3 full. We like to use an ice cream scoop!
Bake 20 minutes or until toothpick inserted into cupcake comes out clean. Cool in pans for 10 minutes, then remove from pans and cool completely.
Beat 1 cup (2 sticks) butter, softened, in large bowl of an electric mixer on medium speed until light, fluffy, and almost white in appearance. Add the apple butter and mix well. Then add in the 2 cups powdered sugar. Beat until well blended. Add more powdered sugar to stiffen the buttercream, or a bit of milk to make the buttercream more spreadable.
Frost the cupcakes using a knife, or decorate with an icing bag and tip (Wilton tip 1M) to make a pretty swirl.