Preheat oven to 300°. Grease the sides and bottom of an 8” or 9” non-stick springform pan (line with parchment paper if the pan isn’t non-stick and then rub butter). If you have cocoa powder, dust the sides of the pan with it as well. Turn it upside down and shake it to remove excess.

Place a large ceramic or glass bowl over a skillet and fill the skillet half way thru with water. Melt butter in the bowl. As soon as butter has melted add the chopped chocolate bar. Stir until melted. Set aside to cool down.

Beat the 6 egg whites either using a stand mixer or using a hand electric mixer in medium-high speed just until soft peaks form, about two minutes.

Slowly add the sugar while still beating, Beat just until the sugar has fully incorporated and the egg whites are fluffy but still are not on the meringue stage, about a minute. Set aside.

To the now cooled down chocolate, add the 6 egg yolks, vanilla, the pinch of salt and the cinnamon and mix.

Add ⅓ of the sugar-egg whites mixture to the chocolate-egg yolk mixture and very gently stir together with a folding motion. Add ⅓ more of the egg whites and gently mix. Add the remaining ⅓ of egg whites and repeat until the color looks homogenous.

Pour the cake batter in the pan and bake for 40 minutes. Remember that at the end the cake will be tall and puffed but it will deflate and crack on top once you take it out of the oven. Let it cool down completely before releasing from the pan.

Dust with plenty of cocoa powder for serving and spoon some whipped cream or ice cream on top.