3 walnut brownie cocoa fudge frosting Recipes

butter, sugar, brown sugar (packed), vanilla, eggs, flour (unsifted), unsweetened baking cocoa, baking powder, baking soda, plain yogurt (at room temperature ), walnuts (toasted and coarsely chopped ), butter, unsweetened baking cocoa, powdered sugar, milk, vanilla, walnuts (toasted and coarsely chopped, for garnish )

butter (for brownies), butter (for frosting ), cocoa, sugar, eggs (reserve 1 for frosting), flour, vanilla (reserve 1/2 tsp for frosting), salt, walnuts (or any nut you like-can be omitted), semi-sweet chocolate chips, unsweetened baking chocolate or 2 unsweetened chocolate squares, water, powdered sugar