Adjust oven rack to center position and preheat oven to 350°F. Spray a 9x9-inch baking pan with nonstick spray, and make an aluminum foil “sling” to overlap opposite sides of the pan by 4 inches (this will aid in removing the brownies before slicing). Press the aluminum foil into the pan and spray the bottom of the aluminum foil.
Unwrap all of the chocolates, and roughly chop 8 of them; set aside.
16 Ferrero Rocher chocolates
Cut the remaining 8 chocolates in-half; set aside.
Mix the brownies per the instructions on the box for FUDGY BROWNIES and gently mix in the chopped chocolates. Pour the batter into the prepared pan.
18.3 ounces Duncan Hines Chewy Fudge Brownie Mix, 2 large eggs, ¼ cup water, ½ cup vegetable oil
Space the remaining 16 halves of chocolate candies, cut-side up, evenly over the batter, pressing each half of candy about halfway down into the batter.
Place the pan with the batter in the center of the middle rack and bake for 27-30 minutes.
Transfer the brownies to a metal rack to completely cool.
Lift the brownies out using the aluminum “sling” and cut into 16 even slices.