First, the crust: use a rolling pin to crush about 3 dozen chocolate wafers between two sheets of wax paper, reducing the wafers to fine crumbs. (You need about 2 cups of crumbs.)
Melt 6 tablespoons of butter, add the melted butter to the crumbs in a bowl, and mix until all the crumbs are evenly moistened.
Use your fingers to press the crumbs evenly into the bottom and about 1½ inches up the sides of a buttered 9" x 3" springform pan.
Bake at 325 degrees for 10 minutes, remove the crust from the oven, and set it aside.
Now turn the oven up to 375 degrees and put a shallow pan of water on the bottom shelf. This preheats and humidifies the oven so the cake doesn't dry out when it's baking.
Next, make the filling
Use a wooden spoon to cream together the cheese, sugar, and lemon zest.
Beat in the vanilla, the eggs one at a time, and the sour cream.
our the batter into the already-made crust in the springform pan and bake for about 1 3/4 hours at 375 degrees. (Leave the pan of water in the oven during baking.)
Chill the baked cake overnight.
Then slip a thin knife blade very carefully between the crust and the pan's side just to loosen it. Finally open the pan's latch and remove the side.
For the chocolate top:
Put 4 ounces of chopped bittersweet chocolate in a bowl.
Heat ½ cup of cream with a tablespoon of sugar to a simmer stirring until the sugar dissolves.
Pour the hot cream over the chocolate in the bowl, stir to dissolve the chocolate
Let the mixture cool until it's the thickness you want, and pour/spread it over the top of the cake, allowing some to run down the sides.
For the cherries:
Mix the cornstarch with the sugar, add the cherries and stir, add the water and vanilla, and heat the mixture to a boil, stirring constantly.
Then quickly turn the heat down to simmer, cook until thickened (this happens fast!), and taste it.
Add a little more lemon juice or sugar if you wish.
Group some of the cherries at the center of the cake top and distribute the rest evenly. Drizzle cherry syrup artistically.
Finally shave bittersweet chocolate curls off a chunk of the stuff and sprinkle/arrange them generously on the cake.
Take a moment to congratulate yourself on your achievement, and then Enjoy!