Giant S’mores Cake for a Casual Wedding!

Instructions

1. Preheat the oven to 350°F (180°C). Grease and line the following size pans, so that the parchment comes well above the sides of each pan (3-inches):

Two 9-x-13-inch (23-x-33 cm)pans
Two 9-inch (23 cm) square pans

2. Heat the butter and milk in a large saucepan over medium heat until the butter has melted and then stir in the brown sugar, graham cracker crumbs, and vanilla – this will make a fluid paste. Remove from the heat.
3. Have all of the other ingredients (except the fudge filling) on hand and layout all four of your pans. Arrange an even layer of graham crackers to cover the bottom of each pan. Ladle a third of the paste onto the crackers, between the 4 pans – it will not cover the crackers fully. Sprinkle a third of the marshmallows over this and sprinkle a third of the chocolate chips on top. Now repeat with the second layer of graham crackers, paste, marshmallows, and chocolate chips, and repeat one more time, taking care with this final layer, since it will be the top of the s’mores cake.
4. Bake the s’mores for about 20 minutes for the square pans and 25 minutes for the 9-x-13-inch (23-x-33 cm) pans, until the marshmallows have browned lightly. Cool the pans to room temperature on a rack and then chill for at least 4 hours before assembling.
5. To assemble, remove the 9-x-13-inch s’mores from their pans, peel away the parchment, and place it on a cutting board. Trim away the outside edges, keeping the corners 90°. Use a tape measure and cut enough from one rectangle to join with the other, creating a 12-inch (30 cm) square. You can shave off the joining sides to make them fit well together, and use a little fudge filling as “glue” to adhere them together (the seam will be barely visible). Place this on a large platter or cake board.
6. Trim away the edges of the 9-inch (23 cm) square of s’mores, if needed, and place this on a square cake board (the board can be 8-inches/20 cm, so it is not visible). Place this on top of the 12-inch (30 cm) layer and press and wiggle it into place so that is level.
7. For the final s’mores, cut a 6-inch (15 cm square) from it and place this on a small board (just smaller than the s’more itself. Place this on top of the cake as level as possible.
8. Spoon some of the fudge sauce filling into a piping bag fitted with a large star tip and decorate along the seams of each layer and on top as you wish.

Fudge Sauce Filling

1. Bring the cream, cocoa powder, brown sugar, granulated sugar, and cornstarch up to a simmer over medium heat, whisking often, until smooth. Stir in the chocolate and butter and return to a simmer while whisking constantly. Stir in the vanilla and salt and remove from the heat. Cool to room temperature and then chill for at least 4 hours before using.