01 - Preheat oven to 375°F. Line a 12-cup muffin tin with paper liners or lightly grease the cups.
02 - In a large bowl, whisk together all-purpose flour, poppy seeds, lemon zest, granulated sugar, baking powder, baking soda, and salt.
03 - In a separate bowl, whisk the eggs, whole milk, melted butter, freshly squeezed lemon juice, and vanilla extract until well combined.
04 - Pour the wet ingredients into the dry ingredients and gently mix until just combined, taking care not to overmix.
05 - Divide the batter evenly among the muffin cups, filling each about three-quarters full.
06 - Bake for 16 to 18 minutes, or until a toothpick inserted into the center comes out clean.
07 - Allow muffins to cool in the tin for 5 minutes, then transfer them to a wire rack to cool completely.
08 - Whisk powdered sugar with lemon juice until smooth and pourable, then drizzle over the cooled muffins.