Preheat oven to 350°F. For the Cupcakes, mix flour, baking powder and salt in medium bowl. Set aside.
Beat butter in large bowl with electric mixer on medium speed 30 seconds or until softened. Add granulated sugar and vanilla; beat until light and fluffy, scraping down sides of bowl frequently. Beat in eggs, 1 at a time. Alternately beat in flour mixture and milk on medium-low speed just until mixed. Spoon batter into 12 lightly greased or paper-lined muffin cups, filling each cup 2/3 full.
Bake 12 to 14 minutes or until toothpick inserted into cupcake comes out clean. Cool in pans on wire rack 10 minutes. Remove from pans; cool completely.
For the Frosting, beat cream cheese and butter in large bowl with electric mixer on medium speed until smooth. Add confectioners' sugar and Root Beer Concentrate; beat until fluffy. Set aside.
Make an indentation in the center of each cupcake using the handle of a wooden spoon or a straw, making sure not to break through bottom of cupcake. Spoon Frosting into resealable plastic bag or piping bag fitted with star tip. If using plastic bag, cut a small piece off one of the bottom corners of bag. Pipe a small amount of Frosting into each cupcake. Pipe remaining Frosting onto each cupcake. Sprinkle with colored sugar, if desired.