Preheat the oven to 175-180°C (350°F).
Melt the chocolate chips and butter together in a double boiler with 1/2 cup hot water and the cocoa powder, over low heat.
Add the eggs one at a time to this mixture, beating with an electric mixer. Then add the sugar.
Mix the dry ingredients together in a separate bowl and fold into the wet mixture.
Finally, chop the nuts and add them, folding everything together well with a spatula.
Line a suitable pan with parchment paper before pouring in the batter, and bake in the preheated oven for 40-45 minutes.
Once out of the oven, cut into small cubes and serve alongside milk, tea, or your drink of choice. Note that because of the small amount of flour, this cake won't rise like other cakes, so the best pans to use are shallow, square/rectangular ones.