Line your baking dish with parchment paper for easy removal later. Set aside.
Place the chopped dark chocolate and butter into a microwave-safe bowl. Microwave in 30-second bursts, stirring after each, until the mixture is smooth, glossy, and fully melted. The aroma of rich chocolate and butter will fill the kitchen.
Stir in the sweetened condensed milk and vanilla extract until the mixture is thick, smooth, and shiny, with a luxurious fudgy texture.
Add the crushed cookies or graham crackers to the chocolate mixture. Fold gently with a spatula until evenly coated, creating a sticky, textured batter with crunchy bits.
Pour the mixture into your prepared dish. Use the spatula to spread it evenly across the dish, pressing down lightly to ensure it’s compacted and smooth on top. The surface will look shiny and slightly textured from the cookie pieces.
Sprinkle a pinch of flaky sea salt flakes and chopped nuts or dried fruit on top, pressing them gently into the surface to help them stick and add extra flavor and crunch.
Refrigerate the dish uncovered for at least 3 hours, or until the mixture is firm and set. For faster results, place it in the freezer for about 1 hour, but don’t forget to check for firmness.
Once set, lift the block out of the dish using the parchment paper edges. Place on a cutting board and cut into bars or squares with a sharp knife, wiping the blade clean between cuts for neat edges.
Arrange the bars on a serving plate and enjoy immediately, or keep refrigerated in an airtight container. The glossy top and chewy interior make these treats irresistible at any time.
