Preheat your oven to 350°F (175°C). Line a muffin tin with paper liners.
In a large bowl, whisk together the flour, sugar, baking powder, salt, and poppy seeds.
In a separate bowl, beat the eggs, then add in the milk, melted butter, vanilla extract, and lemon zest.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.
Divide the batter evenly among the muffin cups, filling each about two-thirds full.
Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted in the center comes out clean.
Allow the muffins to cool in the tin for a few minutes, then transfer them to a wire rack to cool completely.