Pre-heat oven to 400°F. Line a 12 cup muffin tin with liners and set aside.
In a mixing bowl, mix the butter till light and fluffy. Add the sugar, zest, vanilla, lemon juice, and mix till smooth.
Add the eggs one at a time mixing after each egg is added. Gently stir in the sour cream.
In a bowl, whisk together the flour, baking powder, baking soda, and poppy seeds. Slowly mix the dry ingredients into the wet until it is just combined.
Scoop batter into the muffin cups (about ¼ cup) per muffin. Place in oven and back 15 minutes. Allow muffins to cool for about 10 minutes before glazing.
For Glaze:
Whisk together powdered sugar, lemon juice, lemon zest, and milk.
Dip the tops of the muffins into the glaze or drizzle over the top. Allow the glaze to set.