Combine whipped topping and marshmallow fluff in a large bowl then whisk until smooth (some marshmallow lumps remaining is fine.) Fold in mini marshmallows then refrigerate until well chilled.

Measure out 2 Tablespoons chocolate chips and reserve, then pour remaining chocolate chips into a medium-sized bowl. Pour coconut milk into a microwave-safe dish then heat for 45 seconds, or until gently simmering. Pour over chocolate chips in the bowl then let sit for 5 minutes before whisking until smooth.

Line a 5x9” loaf pan with saran wrap, letting it generously hang over the edges, then scoop 1 cup marshmallow mixture into the bottom and spread into an even layer. Next add a layer of graham crackers, cutting or breaking graham crackers to fit into an even layer. Add another 1 cup marshmallow mixture then smooth into an even layer, and then add 1/2 cup of the chocolate mixture and smooth into an even layer.

Repeat layers - graham crackers, marshmallow mixture, chocolate - two more times. Cover the top with saran wrap then refrigerate overnight. When ready to serve, remove saran wrap from the top then invert cake onto a cutting board. Gently pull on overhanging saran wrap to remove the cake from the pan then sprinkle top with reserved chocolate chips and crumbled graham crackers. Slice with a sharp knife then serve.