01 - Preheat oven to 350°F. Grease and flour a 9x5-inch loaf pan or line with parchment paper.
02 - In a large bowl, beat the softened butter and granulated sugar together until pale, light, and fluffy.
03 - Add eggs one at a time, mixing thoroughly after each addition until fully incorporated.
04 - Stir in whole milk, fresh lemon juice, and lemon zest until combined. The mixture may appear slightly curdled — this is normal.
05 - In a separate bowl, whisk together all-purpose flour, baking powder, salt, and poppy seeds until evenly distributed.
06 - Gradually fold dry ingredients into the wet mixture, mixing gently until just incorporated. Avoid overmixing to keep the crumb tender.
07 - Pour batter into the prepared loaf pan and smooth the top with a spatula.
08 - Bake for 35 to 40 minutes, or until a toothpick inserted into the center comes out clean.
09 - Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
10 - Whisk together powdered sugar and lemon juice until smooth. Drizzle glaze evenly over the cooled cake before serving.