Preheat oven to 350 degrees. Line a 13x9-inch baking pan with heavy-duty aluminum foil. Spray foil with nonstick baking spray with flour.
In a medium bowl, combine chocolate and butter. Microwave on High in 30-second intervals, stirring between each, until melted and smooth (about 1½ minutes).
In a large bowl, combine chocolate mixture and sugar. Beat at medium speed with an electric mixer until combined. Add eggs, beating just until combined.
In a separate bowl, combine flour, baking powder, and salt. Gradually add flour mixture to chocolate mixture, beating until combined. Beat in water and vanilla. Stir in milk-chocolate morsels. Spoon batter into prepared pan.
Bake for 35 to 40 minutes or until a wooden pick inserted in center comes out slightly sticky. Let cool in pan for 10 minutes. Remove from pan, and let cool completely on wire rack. Drizzle melted white chocolate on top of brownies. Let stand for 30 minutes or until set.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/triple-chocolate-brownies-recipe/