Nutrition information is calculated using an ingredient database and should be considered an estimate
Preheat oven to 350°. Line bottoms of two 8-inch round cake pans with parchment or waxed paper, then grease and flour bottoms and sides of pans; set aside.
Combine flour and baking powder in medium bowl with wire whisk; set aside.
Beat granulated sugar with I Can't Believe It's Not Butter!® Spread in large bowl with electric mixer, scraping sides occasionally, until light and creamy, about 2 minutes. Add eggs and beat until blended. Beat in milk and vanilla. Gradually add flour mixture and beat just blended. Evenly spread batter into prepared pans.
Bake 45 minutes or until toothpick inserted in centers comes out clean. Cool 10 minutes on wire racks. Remove from pans; remove parchment paper and cool completely.
Beat I Can't Believe It's Not Butter!® Spread in medium bowl with electric mixer until light and creamy, about 1 minute. Gradually add confectioners sugar and beat on low speed until blended. Add milk and vanilla and beat until light and fluffy.
Place 1 cake layer on plate. Spread top with 3/4 cup of the frosting. Top with remaining cake layer and frost top and sides of cake with remaining frosting.
To make the creamiest buttercream frosting for your yellow cake, use a stand mixer if you have one. And if you don’t, use an electric mixer and think about something that makes you angry—like fake pockets in women’s pants.