Chocolate Peanut Butter Icebox Cake

Make wafers in a food processor: Combine flour, cocoa powders, sugar, salt, and baking powder in the work bowl of a food processor, pulsing until mixed. Add butter and run machine until it is powdery. Add egg and vanilla and run machine until the dough begins to clump/ball together.

Make wafers with an electric mixer: Beat butter and sugar together until combined. Add egg and vanilla and beat until smooth. Add baking powder, salt, and cocoa and beat until combined. Add flour and mix just until it disappears.

Both methods: Heat oven to 350 degrees F. Divide dough into 6 equal pieces. Roll first between 2 pieces of parchment paper until very, very thin and just over 7 inches across. Slide onto board (parchment paper and all) and place in freezer for 10 minutes, until firm. Once firm, peel back the top piece of parchment paper (it should now come off cleanly, with a gentle pull back) and use a stencil or bowl with a 7-inch rim to trim it into a neater circle. Slide cookie round and lower piece of parchment paper onto a baking sheet. Bake for 10 minutes and let cool completely on paper, which you can slide onto a cooling rack so that you can use the tray again. Repeat with remaining 5 pieces of dough.

While cookies cool, make peanut butter whipped cream: In a large bowl, beat peanut butter, vanilla, salt, and sugar until smooth. Beating the whole time, slowly add heavy cream, a small splash at a time, until peanut butter-cream mixture is loose enough that you can add the rest of the cream without breaking it into clumps. Whip cream, watching it carefully as it’s very easy to overbeat with an electric mixer, until soft peaks form.

Place the first cookie on a cake stand. If it’s sliding around, as cookies do, put a dab of whipped cream down first. Once it softens the cookie, it will make it stick. Thickly frost the first cookie all the way to the edges with about 1/2 cup peanut butter cream. Repeat with remaining cookies, decoratively swirling the top cookie. Garnish with sprinkles or candy.

Place cake in the fridge overnight or ideally closer to 24 hours so that the cookies soften into cake layers. A knife dipped in warm water will make clean cuts.