Cake: Preheat oven to 350°. Grease and flour three 9-inch round cake pans. Line bottoms with parchment or waxed paper; set aside. Combine flour and baking powder in medium bowl; set aside.
Beat sugar with Country Crock® Spread in large bowl with electric mixer until fluffy, about 2 minutes. Beat in eggs, 1 at a time, until blended. Combine milk and vanilla. Alternately beat in milk and flour mixtures until blended. Spread evenly into prepared pans.
Bake 35 to 40 minutes or until toothpick inserted in centers comes out clean. Cool 15 minutes on wire rack; remove from pans and cool completely.
Frosting and Filling: Beat confectioners sugar, Spread and vanilla in large bowl with electric mixer until fluffy, about 3 minutes. Cut a hole in the center of 2 of the layers using a 3-inch round cutter; remove. (Discard the circle slices or enjoy them while decorating!)
Put 1 of the cake layers with a hole on serving plate. Frost top with some of the frosting. Top with the other layer with hole; frost top. Fill hole with candies. Place the remaining layer on top. Frost top and sides with remaining frosting. Decorate, if desired, with colored sprinkles. Refrigerate at least 1 hour before serving.