Preheat the oven to 350°F (175°C) and grease a loaf pan.

In a mixing bowl, whisk together the flour, baking powder, baking soda, salt, and poppy seeds.

In another bowl, cream the softened butter and sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition.

Stir in the lemon zest and lemon juice.

Alternate adding the dry ingredients and buttermilk to the butter mixture, starting and ending with the dry ingredients.

Pour the batter into the prepared loaf pan and smooth the top.

Bake for 50-60 minutes or until a toothpick inserted into the center comes out clean.

Let the bread cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.