Preheat your oven to 350°F (175°C). Grease and flour a 9x13-inch baking pan.
In a large bowl, cream together softened unsalted butter and granulated sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition. Stir in almond extract.
In a separate bowl, whisk together all-purpose flour, baking powder, baking soda, and salt.
Gradually add the dry ingredients to the butter and sugar mixture, alternating with sour cream, beginning and ending with the dry ingredients.
Fold in finely ground almonds until just combined.
Pour the batter into the prepared baking pan, spreading it evenly.
Bake for 30-35 minutes or until a toothpick inserted into the center comes out clean.