This cake has a tiny bit of espresso powder which really enhances the chocolate flavor for chocolate lovers, but does not taste like espresso at all. (piarecipes.com)
You can omit the coffee completely if you like, it just enhances the chocolate flavor A handful of chocolate chips in the batter will compensate for that! (dessertswithbenefits.com)
But yes, maybe adding extra fat could enhance the chocolate flavor even more and make the texture more like a normal brownie. (dishbydish.net)