Cut tomatoes into large chunks. In a large skillet over medium heat, saute garlic in olive oil until golden brown. Add tomatoes, thyme leaves, and salt and pepper to taste. Cook for 7 minutes, or until sauce is thick. Keep warm.
While sauce is cooking, prick eggplants in several places with a fork. Bring a saucepan of salted water to a boil, and add eggplants. Cover and simmer 10 minutes, or until eggplants are tender.
Drain eggplants, and place one on each of four plates. Slit open eggplants, and spoon some tomato sauce inside each one. Garnish each plate with a spoonful of ricotta and a sprig of thyme.