01 - Preheat oven to 350°F (175°C). Generously grease and flour a 10 to 12-cup Bundt pan, ensuring all grooves are coated.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, salt, and poppy seeds. Set aside.
03 - Using a stand mixer or hand mixer, beat butter and sugar on medium speed until pale and fluffy, approximately 3 to 4 minutes.
04 - Incorporate eggs one at a time, mixing well after each addition. Stir in lemon zest and vanilla extract.
05 - Combine lemon juice and whole milk in a measuring cup.
06 - With mixer on low, alternate adding dry ingredients and milk-lemon juice mixture to batter, beginning and ending with dry ingredients. Mix just until combined to avoid overmixing.
07 - Pour batter evenly into prepared pan and smooth surface with a spatula.
08 - Bake for 45 to 55 minutes, or until a skewer inserted into the center comes out clean.
09 - Let cake cool in pan for 15 minutes, then invert onto a wire rack to cool completely.
10 - Whisk powdered sugar, lemon juice, and lemon zest until smooth and pourable. Drizzle over cooled cake and allow glaze to set before slicing.