Directions

Preheat the oven to 350°F. Butter the bottom and sides of an 8-inch springform cake pan.

To make the crust, in a medium bowl, stir together the ground wafers and melted butter until the mixture is evenly moist. Transfer to the prepared pan, patting the mixture onto the bottom and three-quarters up the sides of the pan. Bake for about 10 minutes, and then cool completely on a rack. To make the filling, melt together the chocolate and butter in the top of a double boiler or in a heatproof bowl over barely simmering water, stirring occasionally until smooth. Remove from the heat and let stand for several minutes. In a medium bowl, mix together the eggs, cream, sugar, salt, and vanilla. Mix in the chocolate mixture and stir until well combined. Pour into the prepared crust. Tap the pan several times on a flat surface to eliminate any air bubbles. Bake for 20 to 25 minutes, until the filling has risen to an inch from the top of the pan, is set, and has slightly raised in the center. The center will continue to set, then fall slightly as it cools.

Transfer the tart to a rack and let cool completely, about 2 hours. Chill in the refrigerator, uncovered, until the center is firm, about 4 hours. Remove the sides of pan and sprinkle the top of the tart with cocoa.