Line an 8x8 inch baking dish with parchment paper making sure the edges come up on two sides.
Cut the large marshmallows into pieces and using a kitchen torch, torch them until just charred. Place the softened vanilla ice cream into a large bowl and mix in the marshmallows.
Spread the softened vanilla ice cream evenly in the lined pan and place in the freeze for 20 minutes. Remove and add the coffee layer. Freeze for 20 minutes. Remove and add the chocolate layer. Freeze overnight.
Break the graham crackers in half so that you have 18 squares.
Using the edges of the parchment paper, lift the ice cream on to a clean surface.
Slice the ice cream into 9 equal squares and sandwich between two graham cracker squares.
Place the ice cream sandwiches back in the freezer for at least 10 minutes before serving.