Preheat your oven to 350°F (175°C). Prepare your baking pan by greasing it well or lining it with parchment paper.
In a medium bowl, whisk together sifted cake flour, baking powder, baking soda, kosher salt, and poppy seeds until evenly mixed.
In a large mixing bowl, beat together room temperature eggs and granulated sugar until light and fluffy.
Gradually add softened unsalted butter pieces into the egg mixture while continuing to beat until well combined followed by adding sour cream, lemon zest, and fresh lemon juice.
Slowly incorporate your dry ingredient mixture into the wet ingredients in batches until just combined; avoid overmixing.
Pour your batter into prepared pan and bake in preheated oven for about 65 minutes or until a toothpick inserted comes out clean; once done, let cool before glazing.