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 - In a large mixing bowl, cream butter and sugar until light and fluffy, approximately 3 minutes.
04 - Add eggs one at a time, beating thoroughly after each addition. Mix in lemon juice and zest.
05 - Mix in half the dry ingredients, then add buttermilk, and finish with remaining dry ingredients. Mix until just combined.
06 - Gently fold chopped strawberries into the batter.
07 - Divide batter evenly among cupcake liners, filling each about two-thirds full.
08 - Bake for 16–18 minutes, or until a toothpick inserted in the center comes out clean. Cool in pan for 5 minutes, then transfer to a wire rack to cool completely.
09 - Beat softened butter until creamy. Gradually add powdered sugar, beating until smooth.
10 - Mix in strawberry puree, lemon juice, lemon zest, and salt. Beat until light and fluffy.
11 - Pipe or spread buttercream onto completely cooled cupcakes. Garnish with additional strawberries or lemon zest if desired.