Separate the eggs (1 egg white will not be used). Peel and cut the pear in 1/4-1/2 inch cubes. Butter 6-inch pie pan and sprinkle with breadcrumbs. Shake excess crumbs out of cake pan.
Chop the chocolate in small pieces and melt in together with the espresso coffee powder au-bain-marie or in the microwave. Cool just a little.
Beat the butter with a mixer until soft and add the confectioner's sugar, little by little. Then add the 3 egg yolks, cinnamon, salt and melted chocolate.
Whisk 2 egg whites stiff.
Fold egg whites and flour alternately into the butter-chocolate mixture. Don't overdo it, but make sure your end-result is well-mixed.
Mix in the pear pieces.
Transfer batter into the cake pan and level as much as you can.
Bake cake approx. 50 minutes. Test with a toothpick; the inside of the cake should be dry.
Remove from oven, take out of cake pan and cool complete on wire rack.
Dust with confectioner's sugar and then with cocoa powder.
Notes
Butter and eggs need to be at room temperature.
2.6 oz. chocolate is 2 bars (most brands). I used 70% dark chocolate