Place Florida Orange Juice in a small saucepan and cook over medium heat until reduced to ⅓ cup. Cool and set aside.
Melt chocolate and butter over very low heat in a 3-quart saucepan, stirring often. Remove pan from heat and stir in sugar until mixture becomes smooth
Stir in eggs one at a time, beating after each egg is added. Add reduced Florida Orange Juice, Florida Orange zest and vanilla. Stir until sugar is completely dissolved and mixture is smooth and glossy.
In a small bowl, combine flour, baking powder and salt and stir well. Add flour mixture to chocolate mixture in thirds, stirring to combine. Do not over mix.
Spread brownie batter in a prepared baking pan and bake for 22 to 27 minutes.
Brownies should just start to pull away from the sides of the pan and should still be a bit underdone in the center.
Remove pan to wire rack to cool completely.
While brownies cool, prepare Florida Orange Glaze. In a small bowl, combine powdered sugar and Florida Orange zest. Stir in Florida Orange Juice one tablespoon at a time until the mixture becomes a thick glaze.
When brownies are completely cool, drizzle with Florida Orange Glaze and garnish with Florida Orange zest, if desired.