2 tablespoons pineapple juice (reserved from crushed pineapple)
1 teaspoon vanilla extract
Fresh pineapple wedges and leaves, for garnish (optional)
1 Preheat oven to 350°F. Prepare 2 muffin pans with baking cups.
2 In a large bowl, combine flour, baking powder, baking soda, and salt; set aside. Remove 2 tablespoons juice from crushed pineapple and set aside for buttercream.
3 In large mixing bowl, beat butter and sugar with an electric mixer on medium speed until light and fluffy. Beat in eggs and vanilla extract.
4 Gradually add flour mixture alternately with sour cream and milk; beat until just combined. Add crushed pineapple; mix until incorporated.
5 Scoop batter evenly into prepared muffin pans. Bake 18-21 minutes, or until a toothpick inserted in the center comes out clean. Remove from oven, cool in pan on cooling grid 5 minutes; remove and cool completely before frosting.
6 For the buttercream, in large bowl, beat butter and shortening with electric mixer until light and fluffy, about 1 minute. Beat in vanilla extract.
7 Gradually add sugar, one cup at a time, starting by mixing on low speed then beating well on medium speed. Scrape sides and bottom of bowl often. When all sugar has been mixed in, frosting will appear dry.
8 Add reserved pineapple juice and vanilla; beat until light and fluffy.
9 Pipe or spread buttercream on cooled cupcakes and garnish with fresh pineapple slices or leaves, if using.