Heat 3 tablespoons oil in a 12-inch heavy skillet over moderately high heat until hot but not smoking, then sauté onion, stirring frequently, until lightly browned, about 4 minutes. Add eggplant, bell pepper, and remaining 2 tablespoons oil and cook, stirring occasionally, until eggplant begins to soften, about 5 minutes. Add zucchini, tomatoes, garlic, thyme sprigs, salt, and pepper and simmer briskly, uncovered, stirring occasionally, 15 minutes. Season with salt and discard thyme sprigs.
While sauce simmers, cook pasta in a 6- to 8-quart pot of boiling salted water , uncovered, until al dente.
Meanwhile, sprinkle parsley and chopped thyme on a small plate. Roll goat cheese log in herbs to coat well.
Drain pasta and transfer to a large shallow bowl. Spoon sauce over pasta and serve topped with slices of goat cheese.
