Preheat oven to 350°F (175°C). Line a muffin tin with cupcake liners.
In a bowl, whisk together flour, baking powder, and salt.
In another bowl, beat butter and sugar until light and fluffy (~3 mins).
Add eggs, vanilla, and lemon zest, mixing well.
Alternatively, add the dry ingredients and milk + lemon juice, mixing until just combined.
Fill cupcake liners 2/3 full and bake for 18-20 minutes or until a toothpick comes out clean. Let cool completely.