Preheat oven to 425°F. Grease 10 standard size muffin tins and line with cupcake liners. Set aside.
In a large mixing bowl combine the granulated sugar and lemon zest. Use your fingers to rub the lemon zest into the sugar until the sugar is fragrant and lemony.
Add the melted butter to the sugar, beating until combined. Add the eggs in one at a time, mixing between each until smooth. Add the sour cream, milk, lemon juice, and vanilla extract and mix well.
Add the flour, baking powder and salt and mix until just combined and no streaks of flour remain.
Last, fold in the poppy seeds until evenly distributed. Do not over mix.
Scoop batter into prepared muffin tins, filling about 3/4 of the way. You can use a large cookie scoop or a 1/4 cup measure to keep things consistent.
Sprinkle tops with some sugar if desired. Bake for 5 minutes at 425°F, then turn oven down to 375°F and bake for an additional 12 minutes, or until muffins are golden brown and spring back to the touch. Remove from oven and allow to cool for at least 15 minutes before eating!