01 - Preheat the oven to 350°F. Thoroughly grease and flour a 10–12 cup bundt pan.
02 - In a medium bowl, whisk together the flour, poppy seeds, baking powder, baking soda, and salt. Set aside.
03 - In a large bowl, beat the softened butter and granulated sugar until light and fluffy, approximately 3 to 4 minutes.
04 - Add the eggs one at a time to the butter mixture, beating well after each addition. Mix in the lemon zest, fresh lemon juice, and vanilla extract.
05 - On low speed, alternately add the dry flour mixture and the combined sour cream and whole milk, beginning and ending with the dry ingredients. Mix until just combined to avoid overmixing.
06 - Pour the batter evenly into the prepared bundt pan and smooth the surface. Bake for 45 to 50 minutes, or until a toothpick inserted into the center comes out clean.
07 - Allow the cake to cool in the pan for 15 minutes before inverting onto a wire cooling rack to cool completely.
08 - Whisk together powdered sugar, fresh lemon juice, heavy cream, and lemon zest until smooth and pourable. Adjust consistency by adding more cream to thin or more powdered sugar to thicken.
09 - Once the cake is fully cooled, drizzle the lemon cream glaze over the top. Allow to set before slicing and serving.