Mix flour,baking soda,and salt. Beat butter and sugar in large bowl with electric mixer on med. speed 5 mins or till light and fluffy. Beat in eggs,1 at a time. Mix sour cream,milk food color and vanilla.. Gradually beat in flour mixture on low speed until just blended. Spoon batter into paper-lined muffin cups,filling each cup 2/3 full.
Bake in preheated 350 oven for 20 to 25 mins. Cool in pans 5mins. Remove from pans;cool completely. Spread with frosting.
Frosting: Beat cream cheese,softened butter,sour cream and vanilla in large bowl till light and fluffy. Gradually beat in confectioners' sugar on medium speed till smooth.