Slice the eggplant into thick rounds (1.5 in) and place on a slightly oiled baking sheet. Salt and pepper each round. Place into a 350 degree oven for about 30 minutes, turning over once at the halfway point. While eggplant is baking, saute the onions in some oil until translucent (~5 min.) Add the garlic and mushrooms and plenty of salt (you want to sweat them). Cover and cook for 10 minutes. Add the fennel and thyme and the tomatoes. Cook until the tomatoes begin to give up there liquid (~5 minutes). Slice the baked eggplant into big pieces and add with the basil. Cook 5 more minutes. Reseason with salt and pepper and toss with the pasta.