There are quite a few steps that take this striking cake to a new level, so we better delve right in. Combining melted butter with flour, toasted pecans, a duo of sugars and cinnamon creates extravagant, moist clumps of a buttery streusel which we will add near the end of the assembly. Before we got started on the batter, we needed to work on preparing the chocolate-y filling. Using another dose of toasted pecans, the filling is made by pulsing those nuts with a generous scoop of chopped bittersweet chocolate, granulated sugar, brown sugar and just a few tablespoons of Dutch-process cocoa power in a food processor. While the bittersweet chocolate adds enough punch, the smoothness of the Dutch cocoa ends up adding another enhancing layer to make those of us who are chocolate fiends swoon.
To give a soft, tender crumb to this cake, the batter calls for using cake flour - while all-purpose flour can work as a substitute, I would suggest grabbing a box of cake flour for this recipe. If you are resistant and still want to make this, remove 2 tablespoons of all-purpose flour for every cup called for and add 2 tablespoons of cornstarch in its place. Cake flour is lower in protein, which yields the lovely light texture this has. For a subtle tang, while also working its magic on the tenderness of the cake, the batter is finished off by alternating the dry ingredients into the buttery batter with a couple cups worth of sour cream. This recipe calls for superfine sugar, also called "Baker's Sugar" or "castor sugar", which incorporates more easily and produces a finer texture - if you want to make your own, you can process the more coarse granulated sugar in a food processor until it is as fine as sand.
The layering process of this cake is what makes for such a dazzling appearance - you will end up with four layers of the fluffy batter and three layers of the double chocolate-pecan filling. For a little funky character, a knife is plunged into the batter and swirled around the pan just two times - don't be tempted to go all crazy and mix it up... just two times around will do fine. Those clumpy bits of cinnamon-laced streusel are strewn over the last layer of batter, followed by a little of the leftover filling so you have a hint of what's to come.
This cake gave us one of those moments when you roll your eyes into the back of your head when we took our first forkful. With a superior moist crumb on the inside, it was hard for both of us to stop at our "quality control" slices and not dive right back into the rich cake for one more piece. If we were not having to give this cake away, I would have probably picked at that obscene streusel on top all day! Was it quite laborious to prepare? Yes, however you will find that it is worth every ounce of effort that you put into this coffee cake!
Chocolate Ripple Coffee Cake