To make strawberry velvet cupcake

• Preheat oven to 350 degrees F. Line a 12-cup standard cupcake pan with paper liners and set aside. 
• Whisk together cake flour, baking soda and salt in a small bowl and set aside. 
• Stir together buttermilk, ¼ cup strawberry puree and vinegar in a another small bowl and set aside. 
• Add 4 tablepoons of butter and ¾ cup sugar in a large bowl, beat on high with a hand held electric beater for about 2 minutes (it will look crumbly). Add 1 yolk, vegetable oil and vanilla extract. Beat again on high for 1-2 minutes until creamy. Add half the flour mixture, beat on slow until just combined. Beat in strawberry-buttermilk mixture, beat until just combined and then finish with remaining flour mixture, beating until just combined (DO NOT overmix).
• Wash and dry beaters. 
• Add 2 egg whites into another smaller bowl, beat on high until stiff peaks form. 
• Using a rubber spatula, fold beaten egg whites into the cake batter, until you no longer see streaks of whites. 
• Divide batter evenly in the prepared cupcake pan. 
• Place in the middle rack of the oven and bake for 18-21 minutes or until a toothpick inserted in the middle of a cupcake comes clean. 
• Place pan on a wire rack to cool completely. 

To make strawberry cream cheese frosting

• Add creamcheese and butter into a large bowl, beat with a hand held electric beater for about 2 minutes, until smooth. Add the confectioners sugar and ¼ cup strawberry puree, beat for 1-2 minutes (start low and then build to high).

   If frosting looks too thick then beat in about 2-4 teaspoons milk and beat. 

  If frosting looks thin then beat in about ¼ - ½ cup confectioners sugar. 

Frost cupcake and top with a fresh strawberry if desired

Eat right away or refrigerate (bring to room temperature before eating).