01 - Preheat oven to 350°F (175°C). Thoroughly grease and flour a 10-cup Bundt pan.
02 - In a medium bowl, whisk together flour, poppy seeds, baking powder, baking soda, and salt. Set aside.
03 - In a large mixing bowl, beat butter and sugar until light and fluffy, about 3 to 4 minutes.
04 - Add eggs one at a time, mixing well after each. Stir in lemon zest and vanilla extract.
05 - Mix in fresh lemon juice and sour cream until combined; the mixture may appear slightly curdled.
06 - Gradually fold dry ingredients into wet ingredients, mixing just until combined to avoid overmixing.
07 - Pour batter into prepared Bundt pan and smooth the surface. Bake 45 to 50 minutes or until a toothpick inserted in the center comes out clean.
08 - Allow cake to cool in pan for 15 minutes, then invert onto a wire rack and cool completely.
09 - Whisk powdered sugar, lemon juice, and lemon zest until smooth and pourable.
10 - Drizzle glaze over cooled cake and let set for 10 minutes before slicing and serving.