Preheat oven to 400F (200C). Bring a large saucepan of water to a boil over high heat. Add orzo. Boil, uncovered and stirring occasionally, until tender, about 8 minutes. Drain well, then rinse with cold water.
Meanwhile, slice about 1/2 inch (1 cm) from top of each tomato. Set aside. Using a large spoon, scoop seeds and pulp from tomatoes into a large bowl. Lay tomatoes, cut-side down, on paper towels to drain. Using a potato masher or fork, break up tomato pulp. To remove pits from olives, smash with flat edge of a large knife. Discard pits, then coarsely chop olives. Stir into tomato pulp with orzo, cheese, parsley, garlic, capers, thyme, salt and pepper.
Place tomatoes, cut side-up, in a lightly oiled baking dish. Spoon in orzo mixture, filling to top. Cover with tomato tops. Bake, uncovered, in centre of 400F (200C) oven 15 to 20 minutes. Tomato skins will wrinkle a little. Terrific warm or at room temperature. These make a great side dish for barbecued chicken or steamed fish.
Nutrition (per serving)
Brighten your plate with colourful tomatoes stuffed with orzo.