Cut the eggplant into 1-inch cubes and the zucchini into 1/4-inch-thick slices. Toss with 2 teaspoons salt and place in a large colander. Set a plate on top and place the colander inside a large bowl or in the sink. Set aside at room temperature and drain for 30 minutes. Transfer to a clean kitchen towel and gently squeeze out as much moisture as possible.

Heat the oven to 450°F. Add the eggplant, zucchini, tomatoes, bell pepper, and onion in a shallow roasting pan large enough to fit all of the vegetables in one flat layer. Cut a 1/4-inch slice off the root of the head of garlic and place the garlic in the center of a large square of foil. Drizzle with 1 tablespoon of the oil and season with salt and pepper. Bring up the corners of the foil and crimp to seal tightly. Drizzle the remaining 2 tablespoons olive oil over the vegetables and add the thyme; season with salt and pepper and place in the oven with the wrapped garlic on the oven rack next to the roasting pan. Roast, stirring often, until the onions are browned around the edges and the peppers are crinkly, about 45 minutes.

Transfer the roasted vegetables to a large bowl and cool. Unwrap the garlic and cool. Finely chop the vegetables; stir in the basil. Pull the garlic apart and squeeze the pulp from the individual cloves onto the vegetables; stir well. Crumble in the goat cheese. Season to taste with salt and pepper.

Spoon about 1/2 cup of ratatouille into each crepe. Serve at room temperate or place on a baking sheet and crisp in a 350°F oven for 30 minutes.