Preheat oven to 350°F. Line a 12-cup muffin pan with paper liners.
In a medium bowl, whisk together flour, baking powder, baking soda and salt. Set aside.
In a large bowl, add sugar and lemon zest. Rub together with your fingers until fragrant.
Add melted butter and mix until combined. Beat in eggs one at a time.
Stir in lemon juice and vanilla extract.
Add half of the dry ingredients to the wet ingredients and mix until just combined. Add the buttermilk and mix until just combined. Add remaining dry ingredients and stir until just combined.
Divide batter evenly among prepared muffin cups (they should be about two-thirds full).
Bake for 18–20 minutes or until a toothpick inserted in the center comes out clean.
Let cool for 10 minutes in pan before transferring to wire rack to cool completely.