Strawberry Cupcakes with Vanilla Buttercream Frosting

1.    Preheat oven to 350 degrees. Grease cupcake tins 
2.    Place strawberries in a small food processor, blend until pureed. You should have about 1/3 cup of puree. Add a few more strawberries if necessary
3.    In a medium bowl, whisk together flour, baking powder, and salt. Set aside
4.    In a small bowl, mix together milk, vanilla, and strawberry puree. Set aside
5.    With an electric mixer, cream butter until light and fluffy. 
6.    Gradually add sugar and continue to beat until well combined and fluffy. 
7.    Slowly add eggs, and egg whites and blend until combined
8.    With the mixer on low, slowly add half the flour mixture. Mix until blended.
9.    Add the milk mixture and mix. Then add the remaining flour mixture and blend.
10.    Divide batter evenly in tins, filling them up 2/3.
11.    Bake for 22-25 minutes 
12.    When done, transfer to wire rack to cool before frosting

For the Frosting: 

1.    Beat the powdered sugar and butter together in an electric mixer on medium low speed until the mixture is well mixed. 
2.    Add the milk and vanilla into the butter and sugar mixture
3.    Add food coloring and beat on high until the frosting is light and fluffy
4.    Frost when cupcakes have cooled