01 - Preheat the oven to 350°F. Grease a 9x5-inch loaf pan and line 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, beat the softened butter and sugar until light and fluffy, about 2–3 minutes.
04 - Beat in the eggs one at a time, mixing thoroughly after each addition.
05 - Add lemon zest, lemon juice, milk, and vanilla extract. Mix until combined—the mixture may appear slightly curdled.
06 - Gradually fold the dry ingredients into the wet mixture until just combined. Avoid overmixing.
07 - Pour the batter into the prepared loaf pan and smooth the top evenly.
08 - Bake for 45–55 minutes, or until a toothpick inserted into the center comes out clean.
09 - Let the loaf cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
10 - Whisk powdered sugar and lemon juice until smooth and pourable.
11 - Drizzle the glaze over the cooled loaf. Allow to set, then slice and serve.