Note about Chocolate, Cookies and Walnuts:
For the Chocolate:
The better quality the chocolate, the better the fudge cake. Valrhona, Scharffen Berger, Callebaut, and Guittard all contain a high percentage of cocoa for a richer flavor. Also, this fudge cake is a great opportunity to use your favorite dark chocolate varieties that may have chile pepper, sea salt, raspberries or cherries incorporated into them.
For the Cookies:
You have many options. Besides graham cracker crumbs, I’ve used Vienna Wafers, and a variety of Pepperidge Farms cookies like Milano’s, Brussels and Sugar Cookies. Surprisingly, when you grind up the cookies up in a food processor, mini-prep or blender, even the cream-filled cookies will pulverize into basic cookie crumbs!
For the Walnuts:
If you want glazed walnuts for the topping, heat 2 tablespoons of sugar, 1 tablespoon of water and a pinch of salt in a small skillet and cook until sugar is dissolved. Add walnuts and cook until walnuts are coated, about 3-4 minutes. Spread walnuts onto a baking sheet line with parchment paper. When cooled and hardened, sprinkle walnuts over top of cake.