Line a 9-inch square pan with parchment paper so it covers the bottom and two sides. Leave enough paper on the edges so you can grasp it easily (you'll be pulling the brownies out of the pan using the paper). Grease well.
Place walnuts in a single layer on a baking sheet and roast in the oven for 5-10 minutes, stirring to prevent from burning. Remove and set aside.
In a saucepan over medium heat, melt butter, chocolate and coffee powder, stirring constantly. Set aside to cool slightly.
In a small bowl, mix together flour, cinnamon and salt.
In a large bowl, whisk eggs and sugar, then whisk in the chocolate mixture. Stir in dry ingredients until just mixed. Fold in walnuts and chocolate chips.
Spread the batter into the pan and bake until a toothpick inserted in the center comes out with moist crumbs on it, about 40 minutes. Let cool completely in the pan on a wire rack.
Once cooled, grab edges of parchment and remove brownies from the pan. Cut into squares and serve.
Recipe by Port and Fin at https://portandfin.com/mocha-walnut-brownies/