Preheat the oven to 350°F.
In a medium bowl, mix the flour, baking powder, baking soda, and salt. Set aside.
In the bowl of a stand mixer or a large mixing bowl with a hand mixer, add the sugar, lemon zest, and almond paste (broken into pieces). Mix on low for about 2 minutes until the almond paste is in small pieces.
Add the room temperature butter and beat on medium-high speed for 2 minutes until light and fluffy.
Add the eggs, vanilla, and almond extract. Beat for another 2 minutes until light and fluffy.
On low speed, alternate adding the buttermilk and flour mixture, starting and ending with the dry ingredients. Mix just until combined.
Gently fold in the lemon zest and poppy seeds.
Pour the batter into a 9×9 inch glass pan lined with parchment paper and sprayed with cooking spray. Spread into an even layer.
Bake for 35 minutes.