Preheat the oven to 450ËšF.
Heat 4 tablespoons butter in a skillet over medium heat. Add the onions, thyme, salt and pepper and cook until the onions are golden brown, about 20 minutes.
Shave off the rounded sides of the baguette with a serrated knife and then cut the baguette in half lengthwise to make 2 long slices of bread. Brush both sides with the remaining 4 tablespoons butter. Put the bread slices on a baking sheet and spread with the onions. Garnish with anchovy halves and olives and drizzle with olive oil. Throw that in the oven and bake until the bread is crispy, about 15 minutes. Shower with Parmigiano. Cut into pieces and serve hot.
Edited: October 2nd, 2009