01 - Preheat oven to 375°F. Line a 12-cup muffin tin with paper liners or lightly grease.
02 - In a large bowl, whisk together flour, poppy seeds, lemon zest, sugar, baking powder, baking soda, and salt.
03 - In a medium bowl, whisk eggs, milk, melted butter, lemon juice, and vanilla extract until smooth.
04 - Pour wet mixture into dry ingredients. Gently stir until just combined without overmixing.
05 - Divide batter evenly among muffin cups, filling each about three-quarters full.
06 - Bake 16 to 18 minutes or until a toothpick inserted into the center comes out clean.
07 - Cool muffins in the pan for 5 minutes, then transfer to a wire rack to cool completely.
08 - Whisk powdered sugar and lemon juice until smooth and pourable, then drizzle over cooled muffins.