Line a 9x9-inch baking pan with wax paper or spray with non-stick cooking spray.

In a large bowl, microwave the marshmallows and butter in 20-second increments, stirring between each increment, until melted. Sift in the cocoa powder using a sieve and add the vanilla extract and red food colouring. Stir until fully incorporated before folding in the Rice Krispies just until combined.

Transfer the mixture to the prepared pan and press into the pan and smooth out the top using a spatula sprayed with cooking spray. Cover and refrigerate for at least 1 hour to firm up. Remove from the pan and slice into 16 even pieces. Drizzle with the melted white chocolate. You may return the squares to the refrigerator for a few minutes to allow the chocolate to harden. Enjoy!