Roughly break graham crackers and place them in a large bowl.

In a medium saucepan over medium heat melt butter and sugar.

Mix butter and sugar and add cocoa powder. While mixing, continue to add vanilla extract, instant coffee and heavy cream. Mix in fudge, unifying all ingredients and cook for 3-5 minutes.

When mixture forms bubbles on the sides of the saucepan, add milk and salt; continue cooking and mixing until mixture is uniform and thick.

Pour the hot fudge over the graham cracker pieces and mix so fudge is spread evenly.

Line a bread loaf baking pan with plastic wrap on the inside leaving extra edges for sealing. Coat the bottom of the pan with mini marshmallows and spread them evenly. Transfer fudge-graham cracker mixture into the pan and cover well with the extra plastic wrap edges.

Allow the cake to set in the refrigerator for a minimum of four to five hours or in the freezer for a minimum of one to two hours.

When you are ready to serve, remove plastic wrap and flip onto a serving tray.

Use a cooking torch to lightly burn the marshmallows on the top.