Directions

1. Preheat oven to 350 degrees. In a medium bowl add cake flour, baking powder, baking soda, and salt, whisk 20 seconds, set aside.
   
2. In a large bowl with an electric mixer, whip 1/2 cup unsalted butter and sugar until pale and fluffy, occasionally stop and scrape down bowl throughout entire mixing process. Add egg then mix and then add in egg whites one at a time and mix.
3. In a measuring cup add buttermilk, 1/3 cup strawberry puree, and 1/2 teaspoon vanilla extract and whisk together.
   
4. Working in three separate batches, beginning and ending with flour mixture, add 1/3 of the flour mixture (to the butter mixture) alternating with half of the buttermilk mixture and mixing just until combined after each addition. Fold in the 3/4 cup diced strawberries.
   
5. Divide batter among 12 paper lined muffin cups, filling each 3/4 full. Bake in preheated oven 20-23 minutes until toothpick inserted into center of cupcake comes out clean. If making mini cupcakes bake for 14-17 minutes. Allow to cool in muffin tin several minutes then transfer to a wire rack to cool completely before frosting.
   
6. To make frosting, first add 1/2 cup plus 2 tablespoons strawberry puree to a small saucepan. Heat mixture over medium-low heat, and simmer, stirring occasionally until reduced to 3 tablespoons, about 10-14 minutes (measure, if it isn't 3 tablespoons then continue to simmer). Pour reduced puree into a small bowl then place in fridge until completely cooled.
   
7. In a large bowl with electric mixer, whip 1/2 cup unsalted and salted butter until very pale and fluffy (nearly white, stop and scrape down bowl occasionally throughout entire mixing process).
   
8. Mix in 1 cup powdered sugar, then blend in reduced strawberry puree, and 1/4 teaspoon vanilla extract. Add remaining 1 1/2 cups powdered sugar and continue to mix until frosting is pale and fluffy.
   
9. To assemble cupcakes, place a small mound of small diced strawberries on top center of cupcakes. Pipe frosting around and over berries. Store cupcakes in an airtight container.
   *To prepare strawberry puree, puree strawberries in a food processor then measure out amount needed. For the amount of puree in the recipe, it's about 10 medium strawberries.
   *To substitute buttermilk, add 1 teaspoon vinegar to a measuring cup, then add in enough milk to reach 1/4 cup. Whisk and let rest for 3 minutes.