This is inspired by a recipe in Erin French’s cookbook The Lost Kitchen.
Preheat the oven to 350 degrees.
Place the chocolate wafers and sugar in the bowl of a food processor fitted with the steel blade and process until finely ground. Pour the mixture into a bowl, add the butter, and mix until well incorporated. Press the mixture into the bottom and sides of a 9-inch tart pan with a removable bottom. Place on a sheet pan and bake for 10 minutes. Set aside.
Meanwhile, for the filing, place the 1 cup of chocolate in a medium glass bowl. Heat the cream until it just comes to a boil. Pour the cream over the chocolate, allow it to sit for 1 minute, then stir gently with a whisk until smooth (see note). Stir the eggs and vanilla into the chocolate until smooth and pour into the tart shell. Bake for 18 to 20 minutes, until the chocolate is set on the edges but still jiggly in the middle. Set aside to cool.
For the glaze, put the ½ cup chocolate and the coffee in a glass bowl. Heat the cream to simmering and pour it over the chocolate. Let sit for 1 minute, then whisk until smooth. Gently pour over the chocolate filling (not the crust) and spread to the inside edge of the crust with a knife or offset spatula. Sprinkle with the salt and set aside at room temperature until set. Remove the rim of the tart pan and place the tart on a flat serving plate. Cut in wedges (don’t worry if the crust crumbles) and serve at room temperature.
I use Lindt bittersweet chocolate.
If either chocolate & cream mixture doesn’t melt completely, heat in a microwave for 15 seconds.