Preheat the oven to 350°F (176°C) and line a muffin tin with cupcake liners.
In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
In a large mixing bowl, cream the butter and sugar together until light and fluffy.
Add the eggs one at a time, mixing well after each. Stir in the vanilla, lemon juice, and zest.
Alternate adding the dry ingredients and milk to the butter mixture, starting and ending with the dry. Mix until just combined.
Divide the batter evenly into the cupcake liners, filling each about two-thirds full.
Bake for 16–18 minutes, or until a toothpick inserted in the center comes out clean.
Let the cupcakes cool completely before frosting with lemon buttercream.