Preheat oven to 425 degrees. Line a standard size muffin tin with liners OR spray the wells generously with non-stick baking spray.

In the bowl of a stand mixer, beat butter on medium speed until light and fluffy, about 2 minutes. Add sugar and lemon zest, beat on medium-high for 4 minutes, scraping down the sides as needed. Add vanilla extract, mix to combine. Add eggs one at a time, mixing well after each addition.

In a medium mixing bowl, whisk together the flour, poppy seeds, baking powder, baking soda, and salt.

With mixing speed on low, alternate adding 1/3 of the dry ingredients and the sour cream at a time until everything has been added. Mix just until combined, do not overmix. Let the batter sit for 10 minutes.

Using a large cookie scoop, divide the batter in between the 12 liners. Place in the oven to bake for 5 minutes at 425 degrees, then reduce the temperature to 400 degrees and continue baking for 14-16 minutes or until full set in the centers.

Remove from the oven and allow to cool in the pans for 6 minutes before transferring them to a wire rack to cool completely.

To make the glaze, in a small mixing bowl whisk together the powdered sugar and lemon juice until smooth. Drizzle over warm muffins. Allow to set before serving.