Heat oven to 350℉.
Oil a 9-inch round or square pan and set aside
Using a stand mixer, whisk egg whites until stiff, and set aside
In a medium bowl. combine egg yolks and sugar, and whisk to blend. Whisk in the almond extract and oil. Add almond flour and cardamom. Gently stir a third of the whites into the batter, then gently fold in the rest until just mixed.
Pour batter into prepared pan. Bake until a toothpick inserted in the center comes out clean, about 50 minutes.
Allow to cool for 10 minutes, then remove from pan and finish cooling on a rack. To decorate, dust with confectioners sugar and chopped pistachios.