Preheat your oven to 350°F (175°C).
Grease and flour a 9×5-inch loaf pan or a Bundt pan.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and poppy seeds.
This helps to incorporate the dry ingredients well.
In a large bowl, cream the butter and sugar using a stand mixer until the mixture is light and fluffy.
Add the eggs one at a time, followed by the lemon zest and vanilla extract.
Alternate adding the flour mixture and buttermilk to the butter mixture, beginning and ending with the flour.
Mix until just combined to avoid overmixing.
Pour the batter into your prepared pan.
Bake for 50-60 minutes or until a toothpick comes out clean.
Cool in the pan for 15 minutes before turning out onto a wire rack.