01 - Set oven to 375°F and line a 12-cup muffin tin with paper liners or lightly grease it.
02 - In a large mixing bowl, whisk together flour, poppy seeds, baking powder, baking soda, and salt until evenly distributed.
03 - Rub lemon zest into sugar to release oils, then whisk in eggs, Greek yogurt, melted butter, lemon juice, and vanilla extract until smooth.
04 - Add wet ingredients to dry ingredients and gently fold together until just combined to avoid overmixing.
05 - Divide batter evenly among muffin cups, filling each about three-quarters full.
06 - Bake for 18 to 20 minutes or until a toothpick inserted in the center comes out clean.
07 - Allow the muffins to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.
08 - Whisk powdered sugar with lemon juice until smooth and pourable, then drizzle over cooled muffins and let set before serving.