Mix the graham cracker crumbs, melted butter, and salt in a bowl until the mixture resembles wet sand. Press this evenly into the bottom and up the sides of your tart pan to form a firm crust. Bake at 180°C (350°F) for 10 minutes until lightly golden, then let it cool completely.
In a microwave-safe bowl, heat the dark chocolate and heavy cream in short bursts, stirring between each, until smooth and glossy. This creates a rich ganache that will fill your tart.
Slightly warm the peanut butter in the microwave for about 10 seconds, then whisk it into the melted chocolate ganache until fully integrated and smooth. You should have a thick, velvety mixture.
Pour the chocolate-peanut butter ganache into the cooled crust, smoothing the top with a spatula for an even surface. Place the tart in the fridge and chill for at least 2 hours, or overnight, until set and glossy.
Before serving, sprinkle flaky sea salt and chopped roasted peanuts over the top of the tart for added flavor and texture. Slice with a sharp knife, wiping the blade clean between cuts for neat slices.
Enjoy the tart at room temperature to experience its full lusciousness and rich flavors. Savor each bite of the silky ganache and crunchy topping, celebrating a nostalgic treat elevated to elegance.