3/4 cup mayonnaise
1 tablespoon fresh lemon juice
1 teaspoon Cajun or Creole seasoning blend
1/4 teaspoon hot pepper sauce
1/2 pound andouille sausage, cut into scant 1/4-inch cubes
3/4 cup pecans, toasted, chopped
1 teaspoon salt
1/4 teaspoon ground black pepper
1 1/2 pounds ground beef chuck or ground beef (20 percent fat)
1 1/2 pounds onions, thinly sliced
2 tablespoons olive oil plus more for brushing grill rack
3 garlic cloves, minced
1 tablespoon golden brown sugar
6 large hamburger buns, split
8 ounces crumbled blue cheese
12 pickled okra pods, halved lengthwise*
3 cups watercress tops