Preheat the oven to 350°F (175°C) and line a muffin tin with cupcake liners.

In a mixing bowl, cream together the softened butter and sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition.

Stir in the milk, lemon juice, and lemon zest.

In another bowl, whisk together the flour, baking powder, baking soda, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Scoop the batter into the prepared muffin tin, filling each cup about 2/3 full.

Bake for 18-20 minutes or until a toothpick inserted into the center comes out clean.

Allow the cupcakes to cool completely before frosting.

In a mixing bowl, beat the softened butter until creamy.

Gradually add the powdered sugar, mixing well.

Add the lemon juice and lemon zest, mixing until smooth and fluffy.

If the frosting is too thick, add a tablespoon of milk to reach desired consistency.

Using a spatula or piping bag, frost the cooled cupcakes with the lemon buttercream frosting.

Optional: Garnish with additional lemon zest or a slice of lemon.