01 - Preheat oven to 350°F. Grease and flour a 9x5-inch loaf pan, or line it with parchment paper for easy removal.
02 - In a large mixing bowl, beat the softened butter and granulated sugar together using an electric mixer until the mixture is pale, light, and fluffy—about 3 to 4 minutes.
03 - Add the eggs one at a time, beating well after each addition to ensure full incorporation before adding the next.
04 - Pour in the whole milk, fresh lemon juice, and lemon zest. Stir gently until just combined. The batter may appear slightly curdled—this is normal and will resolve when the dry ingredients are added.
05 - In a separate bowl, whisk together the all-purpose flour, baking powder, salt, and poppy seeds until evenly distributed.
06 - Gradually add the dry ingredient mixture to the wet batter, folding gently with a spatula until just incorporated. Be careful not to overmix, as this can produce a dense texture.
07 - Pour the batter into the prepared loaf pan and use a spatula to smooth the top evenly.
08 - Bake on the center rack for 35 to 40 minutes, or until a toothpick inserted into the center of the cake comes out clean. The top should be golden and spring back lightly when touched.
09 - Allow the cake to cool in the pan for 10 minutes, then carefully turn it out onto a wire rack to cool completely.
10 - In a small bowl, whisk together the powdered sugar and fresh lemon juice until smooth and free of lumps. Drizzle the glaze evenly over the fully cooled cake before slicing and serving.