Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
     1/2  pound         puff pastry
   4      large         onions -- chopped
   3      ounces        prosciutto -- diced
     1/2  teaspoon      thyme
     1/2  teaspoon      rosemary
   2      tablespoons   olive oil
  12      large         black olives in oil -- pitted
                        freshly ground black pepper
                        salt if needed
   1                    egg

Preparation:

Cook onions in oil with herbs until onions are transparent. Add prosciutto and cook 3 minutes. Season with pepper and check salt. Chill. Roll out dough into a rectangle 11" by 9. Cut 4 strips of dough to make the borders and press them on the edges of rectangle. Transfer to cookie sheet and baste edges with beaten egg. Chill 1/2 hour. Preheat oven to 425F. Spread onion mixture on prepared dough. Bake 30 minutes . Reduce oven temperature to 300F, decorate tart with sliced olives and continue baking another 15 minutes.