10 oz Unsalted sweet butter -; (2
          -1/4 sticks)
    10 oz Bittersweet chocolate – (1
          -1/4 cups); finely chopped
     1 tb Instant espresso; optional
          (or 2 tablespoons dark rum);
          -optional
     8    Egg yolks
 1 1/4 c  Sugar
     6    Egg whites
     1 pn Salt
     2 ts Grated orange zest
          === GARNISH ===
          Good unsweetened cocoa
          Powdered sugar
          Blackberry coulis
 Over low heat, warm butter until just melted but not hot. Add
 chocolate and espresso powder or rum and whisk until melted. Cool
 slightly. In a separate bowl beat yolks and half the sugar until
 light in color. Add warm chocolate mixture and mix together. With a
 mixer, separately whip egg whites with a pinch of salt and orange
 zest and add remaining sugar gradually just until firm peaks are
 formed. Stir in one quarter of whipped whites into chocolate mixture
 to lighten it. Carefully fold in remaining whites. Very lightly oil
 or butter a 9-inch springform pan and place a circle of parchment or
 waxed paper on bottom. Pour batter into pan and bake at 350 degrees
 for one hour. Cool and refrigerate if not serving same day. Note that
 cake will have a “cracked” top surface which is part of its charm! To
 serve: Slice in small wedges and dust alternately with good
 unsweetened cocoa and powdered sugar and a tablespoon or two of
 blackberry coulis on plate if desired. This recipe yields one 9-inch
 cake that serves 10 to 12.
                 
                 Yields       
                10 servings