German Coffee Cake With Nuts and Chocolate ( Nusskuchen )

My most requested recipe. It also got me the sweetest compliment I ever had on my baking. - When the five year old french niece of my best friend came visiting with her parents she was very shy. When she had tasted a little of the cake she insisted that everone present, please try the cake immediately, because "c'est le meilleur gateau du monde" - it is the best cake in the world! And that is what my friends call it now when requesting it. :) - We like it topped with a dollop of sweetened whipped cream.

• Ready In: 2 hrs
• Serves: 4-8
• Yields: 18 slices

Ingredients

• For a 9x5 inch loaf pan

• 1  cup flour (130 grams)
• 1 1⁄2 teaspoons baking powder
• 1⁄2 cup unsalted butter, softened, plus
• 6  tablespoons unsalted butter, softened (200 grams total)
• 1  cup  superfine sugar, plus
• 2  tablespoons  superfine sugar (250 grams total)
• 6  eggs, separated in whites and yolks
• 1  pinch salt
• 1⁄2 teaspoon cinnamon
• 3⁄4 cup  semisweet chocolate, chopped into 1/8 inch pieces (100 grams)
• 2 2⁄3 cups ground hazelnuts (200 grams) or 2 2⁄3 cups ground walnuts (200 grams)

• To grease pan

• 1  tablespoon  melted butter
• 2  tablespoons flour

Directions

1. Note: Time for cooling is not included.
2. Preheat the oven to 350°F (180C). For best removal of cake: Thoroughly grease pan with melted butter. Put it in the fridge for 5 minutes. Remove, fill with 2 tablespoons flour, shake pan over the sink until evenly dusted with flour. Discard any loose flour. Keep dusted pan in fridge until filling.
3. Mix flour with baking powder.
4. Beat egg whites with a pinch of salt in a large clean bowl with clean beaters until stiff but not dry. Set aside.
5. In another large bowl beat soft butter and sugar until creamy white and fluffy. Add egg yolks, one at a time, beat until light in color and increased in volume, about 3 minutes.
6. Put nuts and chocolate into bowl with the butter and egg yolks and mix a few seconds on low until just blended.
7. Sift flour over mixture. Don't mix. Put 1 cup of egg white on flour.
8. With a rubber spatula fold flour and the cup egg white into nut mixture, this will be rather stiff, but it does not need to be blended completely.
9. Give rest of egg white on nut mixture and fold it in until completely blended. (If you try to mix in flour without egg white first and then fold in all of egg white at once, the flour mixture will be too firm to do this, therefore the two steps.).
10. Fill batter evenly into pan.
11. Bake in the middle of the oven for 60-75 minutes. If it browns too much reduce heat by 15 degrees and cover loosely with parchment paper.
12. Test doneness by inserting a wooden skewer into the middle of the cake. If only melted chocolate but no crumbs stick to it the cake is done. Remove from oven.
13. Let cool in pan for 10 minutes, then carefully lay it on the side and let cake slip out of form. You may cut with a thin knife along the sides between cake and pan to make sure it will come out.
14. Best eaten while still a little warm but will keep several days. Dust with a little powdered sugar before serving if you like. Cut into 1/2 inch slices. Serve with a dollop of sweetened whipped cream.
15. Note: Using fresh unsalted butter, freshly ground nuts and a really good-quality chocolate are keys in making this cake really good. I usually make it with hazelnuts, and think this tastes slightly better than with walnuts :).