Follow these simple steps to assemble your Fast Choco Fudge Sandwiches. The process is straightforward and requires minimal cooking time, making it perfect for a quick treat.

1. Prepare Your Workspace: Line an 8×8 inch square baking pan with parchment paper, leaving an overhang on two sides. This will make it easy to lift the fudge out later. If you don’t have an 8×8 pan, a similar sized rectangular dish will work; you might just get slightly different thickness or number of servings. Set aside half of your cookies (12-15) and arrange them in a single layer at the bottom of the prepared pan. They should fit snugly. If using graham crackers, you might need to break some to fit perfectly. This will be the bottom layer of your sandwiches.
2. Melt the Chocolate Mixture: In a medium, heavy-bottomed saucepan, combine the sweetened condensed milk, chocolate chips, and butter. Place the saucepan over low to medium-low heat.
3. Stir Continuously: Stir the mixture constantly with a heatproof spatula or wooden spoon. It’s crucial to keep the mixture moving to prevent the chocolate from scorching on the bottom of the pan. Continue stirring until the chocolate chips and butter are completely melted and the mixture is smooth and glossy. This usually takes about 5-7 minutes. Avoid high heat, as it can cause the chocolate to seize or burn.
4. Add Flavorings: Once the mixture is smooth, remove the saucepan from the heat. Immediately stir in the vanilla extract and the pinch of salt. Mix well until everything is fully incorporated. The fudge will be thick and luscious.
5. Pour and Spread Fudge: Carefully pour the hot fudge mixture evenly over the layer of cookies in the prepared baking pan. Use your spatula to spread it out into a smooth, even layer, ensuring it reaches all corners and covers the cookies completely. Work relatively quickly as the fudge will begin to set.
6. Top with Cookies: Immediately arrange the remaining cookies (12-15) on top of the hot fudge layer, directly aligning them with the bottom cookies to create individual sandwiches. Press them down gently into the fudge so they adhere well.
7. Chill to Set: Place the baking pan in the refrigerator. Let the fudge chill for at least 2 hours, or until it is firm and completely set. For a quicker set, you can place it in the freezer for about 30-45 minutes, but be careful not to freeze it solid if you want to cut it easily.
8. Cut and Serve: Once the fudge is firm, use the parchment paper overhangs to lift the entire block out of the pan and onto a cutting board. Use a large, sharp knife to cut between the cookies, following the lines of the top cookies to create individual sandwiches. If the fudge is very firm, you can dip the knife in hot water and wipe it dry between cuts for cleaner edges.
9. Enjoy: Serve your Fast Choco Fudge Sandwiches immediately, or store them in an airtight container.