Preheat oven to 350 degrees. Grease a 9" springform pan. Set aside.

Mix up the streusel and set it aside.

In the bowl of a mixer, combine sugars, oil, and eggs for 2 minutes. Mix in the buttermilk and instant coffee until incorporated. Sift the flour, baking powder, baking soda, salt and cocoa powder into the wet ingredients. Mix by hand, just until combined.

Fold in the sauerkraut and the remaining chocolate chips.

Pour half of the batter into the prepared pan. Sprinkle half of the streusel over the batter. Top with the remaining batter, and finish off with the remaining streusel.

Bake the cake for 45 minutes, or until a toothpick inserted in the center comes out clean. Cool on a wire rack for a few minutes before icing.

Mix the icing ingredients together. Remove the cake from the outer rim of the springform pan. Drizzle with half of the icing. Cool the rest of the way and drizzle with the remaining icing.