Preheat the oven to 350˚F.  Lightly butter a cookie sheet and set aside.

In a double boiler or a metal bowl over a small saucepan of simmering water, melt together the bittersweet chocolate, unsweetened chocolate, butter and crème fraiche.  Set aside and keep warm.

In a separate bowl, combine the vanilla and espresso powder, whisking together to dissolve the espresso.  Stir this into the warm chocolate mixture and set aside in a warm place, being careful not to let it set.

In a medium sized metal bowl, whisk together the eggs, dark brown sugar and granulated sugar.  Place the bowl over a large sauce pan of simmering water and whisk the mixture constantly until it is warm.  Using an electric mixer, beat on high speed until the mixture is pale, 4-5 minutes.  Fold the warm chocolate mixture into the egg mixture. 

Sift together the flour, baking soda and salt, and stir the sifted mixture into the dry ingredients.  Stir in the chocolate chips, toasted walnuts and dried cherries.

Using a size 16 ice cream scoop (available at most kitchen supply shops), or 1/3 cup, scoop the cookie dough onto the cookie sheet.

Place the cookie sheet in the preheated oven and bake for 9-12 minutes, being careful not to overbake.  These cookies are best served the same day they are baked.