01 - Preheat oven to 350°F (175°C). Line a 12-cup muffin tin with cupcake liners.
02 - In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
03 - In a large bowl, beat the softened butter and granulated sugar together using an electric mixer until light and fluffy, about 3 minutes.
04 - Add the eggs one at a time, beating well after each addition until fully incorporated.
05 - Mix in the fresh lemon juice and finely grated lemon zest until evenly distributed.
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 strawberries into the batter using a spatula, taking care not to crush the pieces.
08 - Divide the batter evenly among the cupcake liners, filling each approximately 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 to cool completely before frosting.
11 - Beat the softened butter until creamy. Gradually add the sifted powdered sugar, beating until smooth. Add the lemon juice, strawberry puree, vanilla extract, and a pinch of salt. Continue beating until the frosting is light and fluffy.
12 - Once the cupcakes have cooled completely, frost generously with the strawberry lemonade buttercream. Garnish with fresh strawberry slices or a sprinkle of lemon zest if desired.