1. Line a 9x5" loaf pan with a double layer of plastic wrap and set aside. Chop five chocolate bars into small pieces and place in a heatproof bowl. Microwave on 50% power until melted, about 45 seconds, stirring halfway through, then let cool slightly. Meanwhile, whisk milk and pudding mix in a medium bowl until thickened, about 2 minutes, then whisk in melted chocolate and espresso powder.
2. In a large bowl, beat cream with an electric mixer on high until stiff peaks form. Add marshmallow spread and vanilla and beat on medium until just blended and smooth, about 30 seconds, then increase speed to high and beat until light and fluffy, about 5 seconds.
3. Spread 1 cup marshmallow mixture on bottom of prepared pan. Top with a layer of graham crackers, breaking them as needed to fit. Spread half of pudding over top, then top with a layer of graham crackers and another layer of marshmallow mixture. Repeat layering with remaining graham crackers, pudding, and marshmallow mixture, ending with a layer of graham crackers (top of cake should be as flat and even as possible). Cover pan with plastic wrap and refrigerate overnight.
4. When ready to serve, break remaining chocolate bar into small pieces and set aside. Place a rack in uppermost part of oven and heat broiler.
5. Remove pan from refrigerator and uncover, then gently turn cake out onto a platter and set aside. Place marshmallows on a foil-lined baking sheet and broil until golden, about 1 minute. Working quickly, use a wide, flat spatula to remove marshmallows from baking sheet, then arrange on top of cake along with chocolate and graham cracker pieces. Use a serrated knife to slice cake into pieces, wiping it clean between cuts, and serve immediately.
Source: Hannaford fresh Magazine, July-August 2021