• Preheat oven to 325°F. Spray a standard loaf pan (8.5 in. x 4.5 in.) with cooking spray and set aside.

Make the cake.

• Grate the zest of two lemons into a medium bowl with sugar. Using clean fingers, rub the zest into the sugar to release the oils from the zest. Set aside.
  grated zest of 2 lemons, 1 ⅛ cups granulated sugar
• Juice the lemons. Set the juice aside for use in the cake and the glaze.
• In a medium bowl, whisk together flour, poppy seeds, baking powder, and salt. Set aside.
  1 ⅞ cups cake flour, ¾ teaspoon baking powder, ¼ teaspoon salt, 2 Tablespoons poppy seeds
• In the bowl of a stand mixer using a paddle attachment (or in a large bowl using a handheld electric mixer), cream the butter and sugar by first beating butter on high speed until smooth and creamy (about 30 to 60 seconds) and then adding the sugar with lemon zest and beating on medium-high speed until light and fluffy (about 2 minutes).
  12 Tablespoons unsalted butter
• Add the vanilla and beat until blended.
  ½ teaspoon vanilla extract
• Slowly add the eggs, one at a time, beating on medium speed until blended.
  4 large eggs
• Add the lemon juice and vegetable oil and beat until blended. The batter will appear curdled, but don't worry; it will come back together when the flour is added.
  2 Tablespoons lemon juice, 2 Tablespoons vegetable oil
• Add the sour cream and beat until well combined.
  ¼ cup full fat sour cream
• With the mixer running on low speed, gradually add the flour mixture and stir just until blended.
• Pour the batter into the prepared pan and bake for 1 hour and 15 minutes or until the cake is domed and golden and a toothpick inserted into the center of the cake comes out clean or with just a few moist crumbs. Let the cake cool in the pan for 10 minutes before carefully turning the pan over to remove the cake. Let the cake cool completely on a wire rack.

Make the glaze.

• When the cake is completely cooled, make the glaze. Add confectioners' sugar and lemon juice to a small bowl and whisk to combine. Slowly add milk, stirring until the glaze is thick but pourable. You might not need to use all of the milk.
  1 cup confectioners' sugar, 1 Tablespoon lemon juice, 1 Tablespoon whole milk
• Place the cake on a cooling rack on top of a plate and slowly pour the glaze over the top of the cake. Let the glaze set before slicing and serving the cake.