First, weigh the butter and let it come to room temperature. If needed, microwave it for a few seconds to soften it.

Now weigh the powdered sugar and mix it with the softened butter until well combined.

Next, separate the egg whites from the yolks. Add the yolks to the butter-sugar mixture and mix well. Set the egg whites aside for later.

Then weigh the chocolate and melt it using a double boiler (bain-marie) or microwave. You can use any chocolate you like—milk chocolate will be sweeter, while dark chocolate will be richer depending on the cocoa percentage. Add the melted chocolate to the butter mixture and combine well.

Beat the egg whites until stiff peaks form. Gently fold them into the chocolate mixture with slow, folding motions to keep the mixture airy. Refrigerate while preparing the next step.

Decide on the dish you’ll use for the cake. Test how the cookies will fit before dipping them in milk. In a shallow dish, warm a bit of milk, then quickly dip the cookies just until they soften slightly—don’t leave them too long, or they’ll fall apart.

Take the chocolate mixture out of the fridge. Begin layering: start with a layer of cookies, then a layer of chocolate cream, another layer of cookies, and repeat until the final layer is chocolate. Cover the sides as well.

Finally, decorate as desired and let the cake set in the fridge for at least 3–4 hours to firm up. I decorated mine with chocolate meringues, melted dark chocolate, and a sprinkle of powdered sugar.