Prep: 20 minutes; Cook: 5 minutes. To keep the filling from getting mushy, cook the tomatoes right after you've stuffed them.
Cut tomatoes in half crosswise. Use your finger to push out and discard seeds; use a paring knife to cut out the pulp, leaving 2 shells. Chop pulp, and transfer to a medium bowl. Place hollowed tomatoes, cut sides down, on a paper towel; drain 5 minutes. Add croutons, goat cheese, olives, dressing, and thyme or basil to pulp; mix well. Mound mixture into hollowed tomatoes.
Place tomatoes on a baking sheet or broiler pan. Broil 4-5 inches from heat until hot and cheese melts (about 5 minutes). Serve immediately.