To make the cookies: In a bowl, whisk together flour, cocoa, and salt. With a mixer, cream margarine and sugar until fluffy.

Add egg and mix well. Slowly add flour mixture and mix until well incorporated.

Divide dough into two pieces. Form two cylinders, about one and 1/2 – two inches (four to five centimeters) in diameter. Wrap well with plastic wrap and freeze for one hour.

Meanwhile, prepare the brittle: Line a baking sheet with Gefen Parchment Paper and spray with Glicks Cooking Spray. Place sugar in a pan (preferably nonstick) and melt over medium heat until it becomes completely liquid. Watch carefully and remove from heat as soon as it’s melted. Whisk in margarine to melt quickly and stir in peanuts. Pour onto prepared baking sheet and spread out thinly. When brittle is fully cooled and hardened, break into small pieces and crush.

Once cookie dough is ready, preheat oven to 350 degrees Fahrenheit (175 degrees Celsius).

Slice cookie dough into 1/4-inch (0.6-centimeter) slices. Place on a lined baking sheet and bake for nine minutes. Allow to cool.

Mix all frosting ingredients with a whisk until smooth. Dip each cookie halfway into frosting. Top with crushed peanut brittle.

To use cookies as a dessert, beat pareve whipping cream until stiff and add in remaining peanut butter frosting. Pipe some cream on one cookie and cover with a second cookie. Pipe some more cream and top with one more cookie, then with a small dollop of cream on top. Finish it off with a sprinkling of peanut brittle.