Preheat the oven to 350* c.set baking pan with aluminum foil, and spray with the cooking spray, Stir together the butter, sugar, eggs and vanilla in a medium bowl. Add the flour, hot chocolate mix, salt and baking powder and stir until just combined. Stir in half the chocolate chips. Spread the mixture in the prepared baking pan,Bake until the brownie begin to pull away from the edges of the pan and are set in the center, 20-25 minutes, Remove from the oven immediately.