01 - Preheat the oven to 350°F (175°C). Thoroughly grease and flour a 10-cup Bundt pan to prevent sticking.
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 the softened butter and granulated sugar together until light and fluffy, approximately 3 to 4 minutes.
04 - Add eggs one at a time to the creamed mixture, mixing well after each addition. Stir in lemon zest and vanilla extract.
05 - Blend in fresh lemon juice and sour cream until just combined, noting the batter may appear slightly curdled.
06 - Gradually fold the dry ingredients into the wet mixture, stirring only until incorporated to avoid overmixing.
07 - Pour the batter evenly into the prepared Bundt pan and smooth the surface.
08 - Bake for 45 to 50 minutes or until a toothpick inserted into the center comes out clean.
09 - Allow the cake to cool in the pan for 15 minutes, then invert it onto a wire rack to cool completely.
10 - Whisk together powdered sugar, fresh lemon juice, and lemon zest until smooth and pourable.
11 - Drizzle the glaze over the cooled cake and let it set for 10 minutes before slicing and serving.