Preheat oven to 350f/180c degrees. Butter a Bundt pan/fluted cake tin. Line bottom with parchment paper; spray paper with non stick cooking spray and set aside.
Dissolve the instant coffee into the warm water. Set aside.
In a food processor or mixer, mix the together the flour, brown sugar, granulated sugar, cocoa powder, baking powder, and salt.
Add the butter, eggs, oil, vanilla and coffee mixture. Beat the mixture until smooth (scraping the edges as you go).
Finish by folding in the chocolate chips.
Pour the batter into the pan and bake 30 – 35 minutes or until a cake tester inserted into center of cake comes out clean or with a few moist crumbs.
Cool in pan on wire rack 15 minutes. Invert cake onto wire rack; remove parchment paper. Leave bottom-side up for icing and cool completely.
For the frosting:
In a large mixing bowl combine all of the ingredients except for the hot water and mix well. Add the hot water one tablespoon at a time until it reaches the desired consistency (I make mine quite thick, but thin enough to pour). Pour slowly to top the cake.