Preheat oven to 350°F degrees. Place Square Flexipat or Fluted Square Mold on Perforated Baking Sheet and set aside.
In Stainless Mixing Bowl, stir together the melted butter, sugar, salt, vanilla, cocoa, and eggs. Stir in the almond flour and baking powder. Pour batter into the Square Flexipat and spread out evenly with the Offset Spatula. Sprinkle nuts on top of brownie batter.
Bake the brownies for 33 to 38 minutes, until the top is set; and a cake tester or toothpick inserted in the center comes out clean or nearly so.
While the brownies bake, bring balsamic to a boil in a small saucepan, then reduce temperature to low. Simmer balsamic about 10 minutes, stirring occasionally, until balsamic thickens. When balsamic sticks to the back of a spoon, the reduction is done. Allow to cool. It will continue to thicken as it cools.
Remove the brownies from the oven, drizzle reduction on the top and allow to cool for about 15 minutes before cutting.Once the brownies are cool, store in Be Save or an airtight container at room temperature.