FOR THE BROWNIES: – 3/4 cup (170g) unsalted butter – 2 ounces (57g) unsweetened chocolate, roughly chopped – 1/4 cup + 2 tablespoons (31g) unsweetened cocoa powder – 1 & 3/4 cups (350g) granulated sugar – 3 large egg – 1 teaspoon vanilla extract – 1 cup (120g) all-purpose flour – 1/2 teaspoon salt – 1 to 1 & 1/2 cups Oreo cookie pieces (approximately 10 to 12 cookies) FOR THE FROSTING: – 1/2 cup (113g) unsalted butter, softened – 1 & 1/2 cups (165g) confectioners’ sugar, sifted – 2 tablespoons milk – 1 teaspoon vanilla extract – 1/4 teaspoon salt – 3/4 - 1 cup finely crushed Oreos (approximately 8 to 10 cookies) – more cookies for garnish (optional)