-
Preheat the oven to 375°F.
-
Lightly grease a 9" springform pan.
-
To make the crust
-
Crush, grind, or otherwise pulverize the chocolate wafers. This is a great way to use your food processor. But you can use a rolling pin, too.
-
Add the melted butter and process briefly, or if doing this by hand, toss the crumbs with the butter until the mixture is evenly crumbly.
-
Press the moist crumbs into the bottom and partway up the sides of the prepared pan. The cheesecake batter will go above the pressed sides, so make the top edge even around the pan to make it beautiful. Place the pan on a baking sheet to catch any drips of butter.
-
Bake the crust for 15 minutes. Then, remove it from the oven and set it aside to cool as you make the filling.
-
Reduce the oven heat to 350°F.
-
To make the filling:
-
Combine the coffee or espresso and chocolate chips in a small saucepan, microwave-safe bowl, or large cup. Heat frequently at 30 second intervals, in the microwave or stove top depending on the container and stirring, until the chips melt and the mixture is smooth. Remove from the heat and set the mixture aside to cool.
-
In a large mixing bowl, beat the cream cheese and sugar at low speed until thoroughly combined. Scrape the bottom and sides of the bowl, and beat briefly, just until smooth. You can do this by hand with a whisk if the cream cheese is very soft.
-
Add the eggs one at a time, beating to combine after each one.
-
Stir in the vanilla, then the flour.
-
Add the chocolate/espresso mixture, beating slowly until thoroughly combined. Scrape the bottom and sides of the bowl; beat briefly, just until smooth.
-
Pour the batter over the cooled cookie crumb crust in the pan. Place the pan on a baking sheet, making it easier to get the cake in and out of the oven safely.
-
Bake the cake (remember, the oven temperature should be 350°F) for 45 to 50 minutes, until a toothpick inserted into the cake 1" from the outside edge comes out clean. A digital thermometer, inserted at the same point, should read 175°F. The center may not look set; that's OK. You want this to be slightly underdone as it will continue to cook as it cools.
-
Turn off the oven, crack the door open several inches, and allow the cake to cool in the oven for 1 hour. You can also prop your oven door open just a crack with a wooden spoon.
-
Remove the cake from the oven and set it on a rack to finish cooling.
-
When it's completely cool, cover the cake, and refrigerate for at least 6 hours or overnight.
-
Serve this rich cheesecake in small slices, with whipped cream and berries if desired.