Pink passion cake

1/2 cup (1 stick) plus 1 tablespoon butter, softened
2/3 cup sugar
1 teaspoon vanilla extract
2 egg yolks, at room temperature
1 egg, at room temperature
1 cup sifted all-purpose flour
1/2 teaspoon EACH: baking powder, baking soda
1/4 teaspoon salt
1/3 cup dairy sour cream, at room temperature
1/2 cup strawberry preserves
Rosie`s Buttercream:
1/2 cup (1 stick) butter, softened
1 1/4 cups confectioners` sugar
1 cup whipping cream, chilled
Red food coloring

Preheat oven to 350 degrees F. Cream butter and sugar in large mixing bowl until light and fluffy. Beat in vanilla. Beat on medium-high speed 2 minutes, scraping bowl occasionally. Add yolks, one at a time, beating after each addition. Add egg; mix well. Resift flour into small bowl with baking powder, baking soda and salt. Add flour mixture alternately with sour cream to butter mixture, beating on low speed just until smooth. Spread evenly in buttered 9-inch heart-shaped pan. Bake about 35 minutes or until golden and top springs back when lightly touched and wooden pick inserted in center comes out clean. Cool completely in pan on wire rack. Using a serrated knife, carefully cut cake horizontally into two layers. Place one layer on serving plate. Spread strawberry preserves evenly over top; spread pink Rosie`s Buttercream over preserves. Place remaining cake layer on top. Frost top and sides with pink Rosie`s Buttercream. Spoon white Rosie`s Buttercream into a pastry bag fitted with desired decorating tip; pipe icing decorations onto cake as desired.
Rosie`s Buttercream: Place butter, sugar and cream in work bowl of food processor; process 5 minutes or until light and fluffy, stopping machine frequently to scrap sides. Transfer to medium mixing bowl. Beat on medium-high speed 15 to 20 minutes or until light and fluffy. Reserve 3/4 cup white buttercream for piping. Stir red food coloring, a few drops at a time, into remaining buttercream until pink.