01 - Preheat the oven to 350°F. Grease and line a 9x5-inch loaf pan with parchment paper.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, salt, and poppy seeds. Set aside.
03 - In a large mixing bowl, cream together the softened butter and sugar until light and fluffy, about 2–3 minutes.
04 - Beat in the eggs, one at a time, mixing well after each addition.
05 - Add the lemon zest, lemon juice, milk, and vanilla extract. Mix until combined (the mixture may look slightly curdled).
06 - Gradually fold in the dry ingredients until just combined—do not overmix.
07 - Pour the batter into the prepared loaf pan and smooth the top. Bake for 45–55 minutes, or until a toothpick inserted into the center comes out clean.
08 - Let the loaf cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
09 - For the glaze, whisk powdered sugar and lemon juice until smooth and pourable. Drizzle over the cooled loaf.
10 - Allow glaze to set, then slice and serve.