Preheat oven to 375F degrees. Grease an 8 to 9-inch square baking pan.
In a large bowl, toss the almond powder, powdered sugar, and salt. Whisk in the eggs, one by one. Add the melted butter and almond extract. Whisk until combined.
Pour batter into the prepared pan. Bake for 40 minutes, or until golden and center is set. Check around 30 minutes and consider reducing oven temperature to 350F if the edges are browning too quickly. Allow to cool completely before slicing into squares.