Ingredients:3 tablespoons butter1 tablespoon olive oil4 sweet (Walla-Walla, Maui, or Vidalia) or yellow onions (2 lb. total), peeled and sliced very thinly1 firm-ripe pear (8 oz.), rinsed and cut in half crosswise, then lengthwiseSalt and pepper2 sheets puff pastry, thawed but kept cool7 ounces (1 1/2 cups) crumbled gorgonzola or other blue cheese