01 - Preheat oven to 350°F and line a 12-cup muffin tin with cupcake liners.
02 - Whisk together flour, baking powder, baking soda, and salt in a bowl. Set aside.
03 - Beat butter and sugar in a large mixing bowl until light and fluffy, approximately 3 minutes.
04 - Incorporate eggs one at a time, mixing thoroughly after each addition. Blend in lemon juice and zest.
05 - Mix in half the dry ingredients, followed by buttermilk, then remaining dry ingredients until just combined.
06 - Gently fold chopped strawberries into batter to prevent streaking.
07 - Divide batter evenly among liners, filling each about two-thirds full.
08 - Bake for 16–18 minutes until a toothpick inserted in the center comes out clean. Cool in pan for 5 minutes, then transfer to a wire rack.
09 - Beat softened butter until creamy. Gradually incorporate powdered sugar, mixing until smooth.
10 - Blend in strawberry puree, lemon juice, lemon zest, and salt. Whip until light and fluffy.
11 - Pipe or spread buttercream onto completely cooled cupcakes. Garnish with additional strawberries or lemon zest if desired.