Preheat the oven to 350°F (175°C). Grease a loaf pan with butter or non-stick spray and lightly dust it with flour to prevent sticking.

Mix the dry ingredients: In a large bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, and poppy seeds. Set aside.

Combine the wet ingredients: In another bowl, beat together the melted butter, granulated sugar, and eggs until smooth and creamy. Stir in the milk, fresh lemon juice, lemon zest, and vanilla extract.

Combine the wet and dry mixtures: Gradually add the dry ingredients to the wet mixture, stirring gently until just combined. Be careful not to overmix; this helps keep the bread light and fluffy.

Pour into the pan: Transfer the batter into the prepared loaf pan and smooth the top with a spatula.

Bake: Place the pan in the oven and bake for 55–60 minutes or until a toothpick inserted into the center comes out clean.

Cool and glaze (optional): Allow the bread to cool in the pan for 10 minutes, then transfer it to a cooling rack to cool completely. For extra sweetness, drizzle the lemon glaze over the cooled bread. To make the glaze, simply whisk together powdered sugar and fresh lemon juice until smooth and pourable.