1. Preheat oven to 350ºF. Butter bottom and sides of a 9-inch springform pan. Line bottom with parchment paper, then butter the paper. Dust the inside of the pan with cocoa powder, tapping out excess.

2. Put chopped chocolate and butter in a large microwaveable bowl and microwave in 30-second increments, stirring between increments, just until it can be stirred smooth. Let cool.

3. Separate eggs, putting 4 of the whites in the bowl of a mixer and all 6 yolks into the warm chocolate mixture. Discard the remaining 2 whites. Whisk the yolks, coffee, cinnamon, and salt into the chocolate mixture until smooth.

4. Beat the 4 whites on medium speed until they form soft peaks when beaters are lifted, 3 to 4 minutes. Gradually add sugar and beat on high speed until the whites form stiff peaks when the beaters are lifted, 3 to 4 minutes more. Stir 1/4 of the whites into the chocolate mixture to lighten it. Gently fold in remaining whites.

5. Pour into the prepared pan and smooth the top. Put the pan into a larger pan, such as a roasting pan or a rimmed baking sheet, and put both pans in the bottom-third of the oven. Pour boiling water into the larger pan to come about 1-inch up side of cake pan.

6. Bake until torte is just firm to the touch and a toothpick inserted in the center comes out almost clean, 40 to 50 minutes.

7. Remove from water bath and let cool completely on a cooling rack. Spread on an even layer of whipped cream and top with raspberries if you like. Remove outside of springform pan to serve.