Preheat oven to 350 degrees F. Line a muffin pan with 12 muffin liners and set aside.
Cupcakes: Slice strawberries and place them into a food processor. Process until strawberries are a chunky puree. You should have about 1/3 cup of puree.
In a medium bowl, whisk together flour, baking powder, baking soda, and salt; set aside.
In a large bowl add sugar and melted butter, until incorporated. Stir in egg, yogurt, milk and vanilla extract until combined.
Add the dry ingredients slowly to the wet ingredients until no lumps remain. Fold in the strawberry puree. Note the batter will be thick.
Scoop about 2 heaping tablespoons into each cupcake liner, filing them about 2/3 full. Bake for 20 minutes or until a toothpick inserted in the center comes out clean.
Move cupcakes to a wire rack to cool completely before frosting.
Buttercream: Again, slice the strawberries and process them into small pieces. You will want to separate the juice from the pieces before placing them into the buttercream. Set strawberries aside.
In a stand mixer fitted with the whisk attachment, whisk together powdered sugar and butter. Mix on low speed until well blended.
Then increase the speed and whisk for 3 minutes.
Add in the vanilla and cream. Whisk together on medium speed for 1 minute. Then add in strawberries and mix for 30 more seconds. Making sure the buttercream is a spreadable consistency.