Plan Ahead: Make tart and then place in refrigerator for 4 hours before serving. Or prepare one day ahead. You will need an 11x1 inch round tart pan with a removable bottom. This dessert is worth purchasing the pan. You will use the pan again with my Crazy Good Fruit Tart page 291.
Place rack in the middle of the oven. Preheat oven to 400°.
In a medium size bowl mix the flour, sugar and salt together. Slice the cold butter into small pieces and put in with the flour mixture. With a pastry blender work the butter and flour mixture together. (Or you can use your fingers.) When you have the consistency of coarse crumbs slowly add in the ice water, 3 Tablespoons at a time. Stir with a spoon and when the dough holds together nicely without being wet or sticky you have enough water. Divide the dough in half. (If not using all the dough you can wrap one half in plastic wrap and then again in foil to freeze).
Turn the dough out onto a lightly floured surface. Roll the dough into a 12 inch round, using a little more flour if needed. Place the dough into the tart pan, fitting it into place, folding down any extra dough into the sides of the pan.
Place a regular pie pan on top of the crust (it will help the crust to stay in place) and bake at 400° for 25 min. Remove the pie pan just over half way through the baking time.
Remove from oven and let cool on a cooling rack. Remove the bottom of the tart pan. Set the tart aside to cool until ready to fill with the chocolate. Wrap and freeze at this point if not filling. Bake the next tart if doing so.
In a medium size sauce pan melt the chocolate with the sugar over low to medium heat. Stir until smooth. Add the cream and continue to stir over medium heat until it begins to thicken, 5 to 8 minutes. (Should be the consistency of heavy cream.) This chocolate will thicken up as it cools.
Take off the heat and let cool down. Stir a couple of times while cooling.
When your tart is cool and the chocolate has cooled but not set, fill the tart with the chocolate. Place in the refrigerator for at least 4 hours, preferably overnight. Sprinkle LIGHTLY with sea salt before serving.
Variation: Can serve with a dab of whipped cream or Crème Fraîche on the