Preheat your oven to 350°F (175°C).
Make the crust: Grind the chocolate wafers in a food processor until fine and measure out 1 ½ cups of crumbs. Mix with the melted butter until it resembles wet sand.
Press the crust into a 10-inch tart pan with a removable bottom, ensuring it goes up the sides evenly and is well-packed. Using a flat-bottomed measuring cup can help with this.
Bake the crust for 10-12 minutes. Remove and let it cool completely.
Prepare the ganache: Heat the heavy cream in a saucepan over medium heat until tiny bubbles begin to form, but do not let it boil. Remove from heat.
Melt the chocolate: Add the chopped chocolate to the hot cream and let it sit for a few minutes. Then, whisk until smooth and glossy.
Incorporate the butter: Add the butter pieces gradually, whisking until fully combined.
Fill the tart: Pour the ganache into the cooled tart shell, smoothing it out. Refrigerate the tart for at least 2 hours until set.
Add sea salt: Once the ganache has set, sprinkle flaky sea salt over the top.
Pro Tip: To slice cleanly through the rich chocolate filling, run your knife under hot water and wipe it dry before cutting.
Make the whipped cream: In a mixing bowl, whip the heavy cream, vanilla bean paste, salt, and sugar until soft peaks form.
Enjoy your Dark Chocolate Truffle Tart with a dollop of whipped cream!