shortbread crust:
3/4 c cold butter
1/4 c sugar
1 T powdered sugar
2 c flour
1 egg white, lightly beaten
Melt butter in saucepan. Remove from heat and stir in sugars. Stir in the flour and set aside to cool 15 minutes. Press the dough evenly into the sides and bottom of a 9-inch tart pan with a removable bottom. Bake in a 350 oven for 30 minutes. Remove from the oven, brush the shell all over with egg white. Return to oven and bake 8 more minutes. Remove and set shell aside to cool.
chocolate filling:
1 c heavy cream
1/2 c milk
8 oz bittersweet chocolate, chopped
1/4 c sugar
1/4 tsp salt
2 eggs, beaten
Combine the cream and milk in a saucepan and heat just until the cream begins to bubble around the edges. Remove the pan from the heat, and add the chopped chocolate. Let sit for five minutes, then whisk until melted and smooth. Add sugar and salt, whisk until smooth. Let sit for five more minutes to cool. Whisk in beaten eggs until completely smooth. Pour filling into cooled tart shell, and bake at 350 for 15 to 20 minutes until the filling is just set. If the filling bubbles or cracks, remove from the oven — it is overbaking. Cool on a wire rack.
