Add the cooled chocolate mixture and the vanilla and stir to combine with a rubber spatula. Add the flour, baking soda, and salt, and blend again. Chop the semisweet chocolate bar into chunks about half the size of a chocolate chip, then add to the batter and mix in. Let the batter rest for 5 minutes. Line a baking sheet with parchment paper or a silicone baking sheet.
With two soup spoons, drop the batter on the baking sheet to make 12 cookies. Crush the coarse salt gently with the bottom of a glass to break crystals about in half, then sprinkle just 3 or 4 grains on top of each cookie. The idea is to get a chunk of salt in a bite, not to have the whole cookie be salty. Bake for 8 to 10 minutes. The tops will be dry and barely spring back when they are done.
Remove cookies to a baking rack and ALLOW TO COOL BEFORE YOU EAT THEM. They will fall apart if they are not cooled.
at 5:42 PM on Mar. 11, 2010