Place twenty of the butter crackers upside down onto a baking pan in a single layer. Spread each with about 1 teaspoon or so of peanut butter.

Spread the remaining crackers with about a teaspoon or so of marshmallow fluff and then sandwich together with the peanut butter crackers. Place in the freezer for about 10 minutes to allow to set.

Place the dark chocolate chips in a heat-proof bowl and microwave for about 30 seconds on high. Give it a stir and return to the microwave. Continue to heat in short 15-second bursts until smooth and melted through. Dip half of the cookie sandwiches into the melted chocolate, one by one, turning over to coat both sides and then lift up with a fork or long skewer. Place on a baking sheet, lined with parchment paper. Top with sprinkles while the chocolate is still wet.

Repeat this process with the white chocolate, melting in the microwave (or stovetop on a double boiler) in the same way. Dip the remaining sandwiches in white chocolate and top with sprinkles as well. Return to the fridge or freezer until the chocolate has hardened, about 10 to 15 minutes. Serve cold or at room temperature. Leftovers can be kept in the fridge, in an airtight container for up to 4 days. Enjoy!