Preheat oven to 350 degrees. Mix flour, cocoa powder, baking soda and salt in medium bowl. Set aside.
Beat butter and sugar in large bowl with electric mixer on medium speed 5 minutes or until light and fluffy. Beat in eggs. Mix in sour cream, milk, food color and vanilla. Gradually beat in flour mixture on low speed until just blended. Do not overmix. Spoon batter into 30 paper-lined muffin cups, filling each cup 2/3 full.
Bake 18 minutes or until toothpick inserted into cupcake comes out clean. Cool in pans on wire rack 5 minutes. Remove from pans; cool completely.
Vanilla Cream Cheese Frosting: Beat cream cheese, softened, butter, sour cream and pure vanilla extract in large bowl until light and fluffy. Gradually beat in powdered sugar until smooth.
Top cupcakes with frosting in the shape of hearts.