01 - Preheat oven to 350°F. Line a 12-cup muffin tin with cupcake liners.
02 - In a medium bowl, whisk together the flour, baking powder, baking soda, and salt until evenly distributed.
03 - In a large bowl, beat the softened butter and granulated sugar together until pale, light, and fluffy.
04 - Add the eggs one at a time, beating well after each addition until fully incorporated.
05 - Mix in the fresh lemon juice and grated lemon zest until combined.
06 - Add the dry ingredient mixture to the wet ingredients in alternating batches with the milk, starting and ending with the dry ingredients. Mix until just combined.
07 - Gently fold the diced strawberries into the batter using a spatula, being careful not to overmix.
08 - Divide the batter evenly among the cupcake liners, filling each 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 pan and transfer to a wire rack to cool completely.
11 - Beat the softened butter until creamy. Gradually add the sifted powdered sugar, beating until smooth. Mix in the lemon juice, strawberry puree, vanilla extract, and salt. Beat until 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.