Preheat oven to 350°F. For the Cupcakes, mix flour, cocoa powder, baking soda and salt in medium bowl. Set aside.
Beat butter and granulated sugar in large bowl with electric mixer on medium speed 5 minutes or until light and fluffy. Beat in eggs, one at a time. Mix in sour cream, milk, food color and vanilla. Gradually beat in flour mixture on low speed until just blended. Do not overbeat. Spoon batter into 30 paper-lined muffin cups, filling each cup 2/3 full.
Bake 20 minutes or until toothpick inserted into cupcake comes out clean. Cool in pans on wire rack 5 minutes. Remove from pans; cool completely.
For the Frosting, beat cream cheese, butter, sour cream and vanilla in large bowl until light and fluffy. Gradually beat in confectioners' sugar until smooth. Frost cooled cupcakes with Frosting.