Preheat the oven to 325°F Line an 8-by-8-by-2-inch baking pan with parchment paper or heavy aluminum foil, making sure the paper or foil extends beyond the edges of the pan; lightly butter the paper or foil.
In a heatproof container set over, but not touching, a saucepan of barely simmering water, heat the butter and chocolate, stirring constantly, until the mixture is melted and smooth; remove from the heat; set aside to cool slightly.
In a small bowl, combine the flour, baking powder and salt; set aside.
In a large bowl beat the eggs and sugar until fluffy and lightened in color, about 1 minute; add the vanilla and mix until combined; add the chocolate mixture and mix just until incorporated; add the flour mixture and mix just until incorporated; the batter should be smooth; using a spatula, fold in the chocolate-covered caramel pieces; spread the batter evenly in the prepared pan.
Bake the brownies in the preheated oven for about 35 minutes, until a toothpick inserted in the center comes out with moist crumbs; transfer the pan to a wire rack to cool completely; using a small knife, loosen the sides of the brownies from the pan; carefully lift the paper and the whole uncut brownie in 1 piece from the pan; remove and discard the paper; cut the brownie into whatever size you see fit to indulge inches.