Prep the Ingredients. Preheat your oven to 375°F and line a muffin tin with paper liners. Zest and juice the lemons, ensuring you get fresh, vibrant citrus flavor.
Mix the Dry Ingredients. In a large mixing bowl, whisk together the flour, sugar, baking powder, and salt.
Combine the Wet Ingredients. In another bowl, whisk the eggs, milk, melted butter, lemon juice, lemon zest, and vanilla extract until well blended.
Make the Batter. Gradually mix the wet ingredients into the dry ingredients, stirring until just combined (do not overmix, or the muffins will be dense).
Bake to Perfection. Fill the muffin cups about 3/4 full with batter. Bake for 18-22 minutes or until a toothpick inserted in the center comes out clean. Let the muffins cool in the pan for 5 minutes before transferring them to a wire rack.
Add the Lemon Glaze (Optional). In a small bowl, whisk together powdered sugar and lemon juice until smooth. Drizzle over the cooled muffins and sprinkle with lemon zest.