Mix together flour, baking powder, salt, 4 Tbsp cocoa, and sugar in a gallon sized ziplock bag before you leave home. At camp add milk, butter and nuts into bag and mix together. Dump into a 12 inch dutch oven. (Batter will be thick like brownies.) In another bag (marked to indicate that this bag is the pudding part) mix together brown sugar, 4 Tbsp cocoa, cornstarch, and hot (not too hot or it will melt the bag) water. Mix together and gently pour over the batter in the dutch oven. Put on lid and bake for about 45 minutes. Great alone or with whipped topping.