01 - Preheat oven to 350°F. Line a 12-cup muffin tin with paper cupcake liners.
02 - In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt until evenly distributed.
03 - In a large bowl, beat the softened butter and granulated sugar together using an electric mixer on medium speed until the mixture is pale, light, and fluffy.
04 - Add the eggs one at a time, beating well after each addition until fully incorporated before adding the next.
05 - Mix in the fresh lemon juice and finely grated lemon zest until evenly combined.
06 - Gradually add the dry ingredients to the wet mixture, alternating with the whole milk. Begin and end with the dry ingredients, mixing until just combined. Do not overmix.
07 - Gently fold the diced fresh strawberries into the batter using a spatula, being careful not to overmix.
08 - Divide the batter evenly among the prepared cupcake liners, filling each liner about two-thirds full.
09 - Bake for 16 to 18 minutes, or until a toothpick inserted into the center of a cupcake comes out clean.
10 - Remove the cupcakes from the muffin tin and transfer to a wire rack. Allow to cool completely before frosting.
11 - Beat the softened butter until creamy and smooth. Gradually add the sifted powdered sugar, beating until fully incorporated. Add the fresh lemon juice, strawberry puree, vanilla extract, and a pinch of salt. Beat on medium-high speed until the buttercream is light and fluffy.
12 - Once the cupcakes are completely cool, frost generously with the strawberry lemonade buttercream. Garnish with fresh strawberry slices or additional lemon zest if desired.