white cake with strawberry icing

I wanted to serve something pink at Misty's shower so I decided on this cake. Little did I know this baby has been called "pink" for some time now.

white cake with strawberry icing (cookbook: Paula Deen Celebrates!)
1 (18.25 ounce) package white cake mix
1/2 cup butter, softened
3 large eggs

icing
4 tablespoons unsalted butter, softened
4 cups sifted confectioners' sugar, about 1 pound
6 ripe strawberries, hulled and mashed
6 whole strawberries for garnish

Preheat oven to 375 F. Grease and flour a 13x9-inch baking pan.
Blend the cake mix, 2/3 cup water, the butter and the eggs in a large bowl with an electric mixer until well blended, about 3 minutes.
Pour the batter into the pan and bake for 28 to 30 minutes, until the center of the cake springs back when pressed. Cool in the pan on a wire rack for about 15 minutes.
Make the icing: Place the butter and 2 cups of the sugar in the bowl of an electric mixer. Beat at low speed until blended. Add the mashed strawberries and mix at medium speed until well combined. Add the remaining 2 cups sugar and beat until creamy and smooth. The icing should be thick enough to stand up on a spoon. If too thin, add more confectioners' sugar. If too thick, add a teaspoon or two of milk.
Frost the cooled cake in the pan. For decorative effect, make swirls in the frosting with a clean spatula. Garnish with the whole strawberries. Cut into 12 to 16 pieces, and store, covered, in the refrigerator for up to 5 days. Serves 12 to 16.