Special equipment: a 10-inch metal mixing bowl
For the cake: Preheat the oven to 350 degrees F. Line a half sheet pan (18-by-13-inch baking sheet) with parchment paper and spray only the bottom with nonstick cooking spray.
Roll the almond paste between two sheets of parchment paper into a 9-by-14-inch rectangle; set aside.
In the bowl of a stand mixer fitted with the whisk attachment, add the egg whites and salt and whisk just until foamy. Whisk in the cream of tartar. Slowly add 1/2 cup (100 grams) of the granulated sugar and whisk on high speed until stiff peaks form. (Be careful not to overwhip to the point of dryness or clumping.) Transfer the egg whites to a large clean bowl.
In the same stand mixer bowl (you needn't clean it), add the egg yolks, vanilla and the remaining granulated sugar and whisk on high speed until the mixture is pale yellow and forms ribbons when you lift the whisk.
Stir one-third of the egg whites into the yolk mixture. Using a large rubber spatula, gently fold in the remaining egg whites. Sift the cocoa powder over the egg mixture and fold into the batter until just combined. Transfer the mixture to the prepared sheet pan. Using a large offset spatula, spread the batter evenly into the prepared pan. Bake for 25 minutes, or until the cake springs back lightly when touched.
Sprinkle the confectioners' sugar onto a clean kitchen towel in an even layer. Run a very sharp paring knife along the side of the pan and release the cake. Invert the cake onto the towel and remove the parchment.
While the cake is still very warm, place the rectangle of almond paste onto the cake. Using the kitchen towel to help you, roll the cake into a jelly roll and wrap the towel tightly around the cake to keep it in place. Allow to cool completely.
For the coffee simple syrup: Put the coffee and granulated sugar in a small saucepan and heat, stirring, until the sugar is dissolved. Let cool.
To assemble the Charlotte Royale: Line a 10-inch metal mixing bowl with plastic wrap so that the plastic wrap hangs over the side. Cut the jellyroll into rounds 1/3 inch thick. Dip the bottom of each round quickly into the coffee simple syrup and use the rounds to line the bowl. Start at the middle and place them packed tightly together soaked-side down. Use 1/2 cup of the cookie crumbs to coat the inside of the rolls in the bowl, pressing gently with your hands to get in between any gaps in the rolls.
Add 1/2 gallon of the softened chocolate ice cream into the center of the cake-lined bowl, packing it in gently and spreading to even and smooth the top. Add 1/2 cup crushed chocolate wafer cookies in an even layer, then top with the remaining 1/2 gallon ice cream, packing it in gently again and using an offset to spread evenly. Finish with an even layer of the remaining 1/2 cup cookie crumbs. Place in the freezer until firm (at least 4 hours or overnight).
Trim any overhang from the cake base. Invert onto a serving platter and use the plastic wrap to coax the Charlotte out of the bowl. Remove the plastic wrap. Allow the cake to rest for about 30 minutes in the refrigerator to thaw to a temperature where it can be sliced. Slice and serve immediately.
Adapted from "Bake It Like You Mean It: Gorgeous Cakes from Inside Out" by Gesine Bullock-Prado © Stewart, Tabori and Chang 2015. Provided courtesy of Gesine Bullock-Prado. All Rights Reserved.