Preheat oven to 350 degrees F. Grease a 9x9 inch baking pan.
In a medium bowl, mix together the olive oil, sugar, and vanilla. Beat in eggs. Combine flour, cocoa, baking powder, and salt, gradually stir into the egg mixture until well blended. Stir in walnuts, if desired. Spread the batter evenly into the prepared pan.
Bake for 20 to 25 minutes, or until the brownie begins to pull away from edges of pan. Let cool on a wire rack before frosting and cutting into squares.
Pomegranate Balsamic Ganache
Place the chocolate into a medium bowl. Heat the cream, salt, and tangerine zest in a small sauce pan over medium heat. Bring just to a bare simmer, watching very carefully because if it boils for a few seconds, it will boil out of the pot and scorch.
When the cream has come to a simmer, remove the zest, pour over the chopped chocolate, and whisk until smooth. Stir in the Tangerine balsamic.
Allow the ganache to cool, looking for a spreadable consistency before frosting the brownies. Start at the center of the brownies and work outward.