01 - Preheat oven to 375°F. Line a 12-cup muffin tin with paper liners or grease thoroughly.
02 - In a large bowl, whisk together flour, poppy seeds, baking powder, baking soda, and salt until well blended.
03 - Rub lemon zest into sugar with fingertips until fragrant. Whisk in eggs, yogurt, melted butter, lemon juice, and vanilla extract until smooth.
04 - Pour wet ingredients into dry ingredients. Gently fold with a spatula until just combined; avoid overmixing to keep muffins tender.
05 - Divide batter evenly among prepared muffin cups, filling each about 3/4 full.
06 - Bake for 16–18 minutes, or until a toothpick inserted into the center comes out clean.
07 - Let muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.
08 - Whisk powdered sugar with lemon juice, adding gradually to reach desired consistency. Stir in lemon zest if using. Drizzle over cooled muffins and allow glaze to set before serving.