01 - Preheat your oven to 375°F (190°C). 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 combined.
03 - In a separate bowl, rub lemon zest into sugar with fingers until fragrant. Add eggs, yogurt, melted butter, lemon juice, and vanilla. Whisk until smooth.
04 - Pour wet ingredients into dry ingredients. Gently fold with a spatula until just combined. Do not overmix.
05 - Divide batter evenly among 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 - Cool muffins in the pan for 5 minutes, then transfer to a wire rack to cool completely.
08 - Whisk powdered sugar with lemon juice, adding juice gradually to reach desired consistency. Add zest if using. Drizzle over cooled muffins and allow glaze to set before serving.