Preheat the oven to 325 degrees F (165 degrees C).
Cream butter in a bowl using a silicone spatula. Add confectioners' sugar and mix to combine. Mix in almond extract. Work in flour and poppy seeds. Turn dough onto an unfloured board and knead until smooth.
Spray a shortbread mould with non-stick spray. Put dough in the middle of the mould and press into the mould, working from the center to the edges. Prick the entire surface with a fork.
Bake shortbread in the preheated oven until the entire surface is lightly browned, 30 to 35 minutes.
Let shortbread cool in the mould for about 10 minutes. Flip mould over onto a wooden cutting board and use a sharp knife to cut into serving pieces while still warm.
