CHOCOLATE-HAZELNUT COFFEE CAKE WITH HAZELNUT-CORNFLAKE CRUMBS

Steps:

• Combine the flour, brown sugar, cornflakes, hazelnuts, cinnamon and salt in a small bowl and mix to combine. Add the butter and mix thoroughly with your fingers or a fork until all of the butter has been evenly distributed and incorporated into the flour. Form into small to medium clumps with your fingers.
• Preheat the oven to 350 degrees F. Butter an 8-inch square cake pan.
• Whisk together the flour, baking powder, baking soda and salt in a small bowl.
• Beat the butter and granulated sugar together in a large bowl with an electric mixer on medium-high speed until light and fluffy, about 3 minutes. Add the eggs, 1 at a time, beating well after each addition. Beat in the vanilla. Reduce the speed to low and add the flour mixture in 3 batches, alternating with the sour cream, beginning and ending with the flour, beating until just incorporated.
• Spoon half of the cake batter (it will be very thick) into the prepared pan and smooth with an offset spatula. Dollop the chocolate-hazelnut spread on top and carefully smooth with the spatula. Spoon the remaining cake batter on top and smooth the top. Sprinkle on the crumb topping.
• Bake until the cake and topping are golden brown and a toothpick inserted into the center of the cake comes out clean, about 1 hour. Let cool in the pan 20 minutes, then invert onto a plate and re-invert onto a rack to cool completely. When the cake is cool, dust with confectioners? sugar.