01 - Preheat 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 until well blended.
03 - In a large bowl, combine sugar and lemon zest. Rub together with your fingers until fragrant and the oils are released.
04 - Whisk melted butter into the sugar mixture. Add eggs one at a time, then mix in milk, lemon juice, and vanilla extract until smooth.
05 - Fold the dry ingredients into the wet mixture just until combined. Do not overmix to ensure a tender crumb.
06 - Transfer the batter to the prepared loaf pan and smooth the top with a spatula.
07 - Bake for 45–55 minutes, or until a toothpick inserted into the center comes out clean.
08 - Let cool in the pan for 10 minutes, then carefully transfer to a wire rack to cool completely.
09 - Whisk powdered sugar with lemon juice until smooth and pourable. Adjust consistency with additional juice if needed.
10 - Drizzle the glaze over the cooled loaf. Allow the glaze to set before slicing and serving.