Make the strawberry purée by combining all ingredients in a saucepan. Bring to a boil and then simmer over medium-low heat for 15 mins, stirring frequently. Smash or blend the berries. Set aside to cool.
Strawberry Cake
Preheat oven to 350 °F. Line 2 muffin pans with cupcake liners or spray with non-stick cooking spray. Alternately, grease with shortening.
Cream the butter and sugar together until light and fluffy, about 4-5 minutes with an electric mixer.
Add egg whites and vanilla to the butter mixture. Beat until well incorporated. Scrape down the sides of the bowl.
In a large bowl, combine the dry ingredients, flour, baking powder, baking soda and salt.
Alternate between adding the dry ingredients and the milk slowly until both are incorporated into the butter mixture.
Finally add in lemon zest and strawberry puree. Mix until combined.
The batter will be thick.
Scoop into muffin cups, filling them no more than 3/4 full or else you’ll have “muffin tops” Bake for 18-20 mins.
Allow to cool completely before frosting.
Strawberry Buttercream
Beat butter until light and fluffy, 3 to 5 minutes.
Add powdered sugar and mix with the butter.
Slowly begin to incorporate the strawberry purée.
Add the heavy cream and beat on high speed for 5 mins.
Add more powdered sugar if the frosting will not hold a stiff peak.
Notes
Depending on the weather or climate will determine how much liquid is necessary. For climates with more moisture in the air, you may notice it takes a lot of powdered sugar to get a stiff peak. If you get up to 2 lbs (8 cups) of powdered sugar, add a pinch of salt to balance out the sweetness.As a good rule of thumb, don’t dump all the purée in. Slowly add it and watch the texture of the frosting as it’s whipped for 5 mins to incorporate air making it fluffy.
This recipe was calculated using the exact brands and measurements I used to make this recipe. If you are following a strict diet please note changing anything will cause the nutritional info to change. My calculations are intended as a guide only.