Step 1: Preheat and Prepare : Preheat your oven to 375°F (190°C). Line a 12-cup muffin pan with paper liners or lightly grease it with butter or non-stick spray.

Step 2: Mix Dry Ingredients : In a large bowl, whisk together: Flour, poppy seeds, lemon zest, baking powder, baking soda, and salt. Set aside.

Step 3: Mix Wet Ingredients : In another bowl, whisk together: Sugar, melted butter, eggs, Greek yogurt (or sour cream), lemon juice, and vanilla extract. Whisk until smooth and well combined.

Step 4: Combine Wet and Dry Mixtures : Pour the wet ingredients into the dry ingredients. Gently fold together using a spatula until just combined (do not overmix). The batter should be thick but scoopable.

Step 5: Fill Muffin Cups : Divide the batter evenly among the 12 muffin cups, filling each about ¾ full.

Step 6: Bake : Bake in the preheated oven for 18–20 minutes, or until a toothpick inserted in the center comes out clean. Let the muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

Step 7: Prepare the Glaze : In a small bowl, whisk together powdered sugar and lemon juice until smooth and slightly thick. Add lemon zest if desired for extra zing.

Step 8: Glaze the Muffins : Once muffins are completely cooled, drizzle the glaze over the tops using a spoon or piping bag. Allow glaze to set for 10–15 minutes before serving.