Preheat oven to 325º F. Spray an 8x8 baking dish with nonstick baking spray. Set aside.
Whisk together flour, salt and baking powder in a small bowl. Set aside.
Melt chocolates and butter in a medium saucepan over medium-low heat. Remove from heat and stir in sugar, vanilla and eggs. Stir until completely combined and glossy. Stir in dry ingredients until just combined.
Pour half of brownie batter into prepared baking dish. Top with salted caramel sauce and pecans and remaining brownie batter. Place in the preheated oven and bake until a toothpick inserted in the center comes out clean, about 35-40 minutes. Remove from oven and allow to cool completely before serving.