Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
     1/3  cup           olive oil
   1      tablespoon    fresh lemon juice or wine
                        vinegar
   2      tablespoons   fresh basil -- chopped
   1      tablespoon    shallots -- chopped
     1/2  teaspoon      salt
     1/4  teaspoon      freshly ground pepper
   3      large         tomatoes -- cut into slices
                        - 1/2-3/4 inch thick
  10                    green onions -- trimmed, up to 12
                        including 4" of green tops
   1      sprig         fresh basil or
                        parsley

Preparation:

Firm tomatoes, even those that are slightly green, should be used for this recipe. They are less juice and hold their shape better when grilled than fully ripe ones. Fresh basil is wonderful with tomatoes, but you could also use chopped tarragon or even parsley in the basting sauce. Serve warm or at room temperature, with grilled lamb or fish. Prepare a fire in a grill. Position the oiled grill rack 4-6 inches above the fire. In a small bowl stir together the oil, lemon juice or vinegar, chopped basil, shallots, salt and pepper. Arrange the tomatoes and onions on the rack. Grill, turning them two or three times and brushing with the oil mixture, about 5 minutes. If the onions are large, they might take 1 or 2 minutes longer. Transfer the tomatoes and onions to a platter and Garnish with basil or parsley sprigs. Source: Williams-Sonoma Kitchen Library: Grilling