Place the chocolate wafers in a food processor and pulse until it resembles a fine crumb.
Place these in a bowl along with the walnuts, cocoa powder salt.
Mix, then add the condensed milk and fully combine.
Add the bittersweet chocolate and mini chocolate chips and mix.
Pour into a loaf pan that has been greased and lined with parchment paper.
Smooth the surface and top with extra walnuts, gently pressing to stick them to the brownie.
Cover with plastic wrap and refrigerate until firm, 1-2 hours.
Slice into squares and enjoy!