Using a cleaver or other heavy knife, chop the crunch into quarter-sized pieces.

Allow the crunch to cool, undisturbed, for at least 30 minutes.

Remove from the heat and quickly whisk the baking soda into the crunch the mixture will expand and aerate quickly, in a matter of seconds. When the crunch reaches 270 F, increase the heat to high and stir constantly until the crunch reaches 305 F.Measure the baking soda into a ramekin or cup and place near the stovetop, along with a large whisk. Meanwhile, heavily coat a 13-by-18-by-1-inch baking sheet with nonstick baking spray.Add the sugar, coffee and corn syrup to the pot and cook over medium-high heat, stirring occasionally with a heatproof silicone spatula until the mixture reaches 270☏, about 10 minutes. Make the coffee crunch: Attach a candy thermometer to the side of a 4- to 6-quart heavy pot.Wrap the cake in plastic wrap and refrigerate until you are ready to assemble the cake. Run an offset spatula between the cake and the bottom to release it. Holding the rim of the pan with one hand, press the bottom of the pan up and out. Run an offset spatula around the sides of the cake to loosen it from the pan.Let the cake cool completely on a cooling rack, about 45 minutes (removing the cake when it is still warm will cause it to deflate and likely tear).Bake the cake for 55 minutes to 1 hour, until it is golden brown and a toothpick inserted in the center comes out clean. Pour the batter into the prepared cake pan and smooth the top with a spatula.Gradually fold in the dry ingredients, approximately 1 cup at a time, until fully incorporated. Using a rubber spatula, fold the yolk mixture into the egg whites.Add the lemon zest and juice and beat just until incorporated, about 15 seconds.

Add the remaining ½ cup sugar and beat until stiff, glossy peaks form. Add the cream of tartar and continue beating until the egg whites form soft peaks. Add the egg whites to the large mixer bowl (or another bowl) and beat until frothy.If using a stand mixer, transfer the mixture to a large bowl and wash and dry the mixer bowl and whisk (or wash the beaters). Gradually add the water, oil, and vanilla, mixing well. In the bowl of a stand mixer fitted with the whisk attachment (or in a large bowl, using a handheld mixer), whip the yolks and ¼ cup sugar on medium speed until thick and pale yellow, about 4 minutes.Sift together the flour, ¾ cup of the sugar, and the salt into a medium bowl.Coat the bottom and sides of a 9-inch round cake pan with a removable bottom with nonstick baking spray. Make the cake: Position a rack in the center of the oven and heat the oven to 350 F.

Crunch a bunch cake