PREHEAT OVEN TO 180ºC . Line an 8.75-by- 34 cm glass or metal pan with a large piece of aluminum foil, smoothing it into the corners. Butter the foil. In a large bowl, cream the butter with the sugar together until it is light in color. Stir in the melted chocolate. Add the vanilla, then add the eggs, beating until blended. In another bowl, combine the flour and salt. Add the walnuts and all the bits, tossing to coat them with the flour. Scrape the flour, nuts and bits into the bowl with the butter, and stir with a wooden spoon just until all the ingredients are mixed. Do not over-beat. Scrape the batter into the prepared pan, holding the foil so that it does not move. Place the pan in the middle of the oven and bake until a toothpick inserted in the center comes out almost clean, about 50 minutes. Remove the pan and let it stand for an hour, then cover the pan with foil and place it in your freezer for at least 1.5 hours or in your refrigerator overnight. Turn the cooled brownies out onto a clean workspace, lift off the foil and cut into 32 squares. Store in the refrigerator or the freezer in an airtight tin. ----