Cube eggplant in about 1 1/2 inch cubes, sprinkle with salt and let sit for 10 minutes in a colander.
Preheat oven to 420°F (or 220°C) and grease a baking pan with 3 tablespoons olive oil.
Cube zucchini and bell pepper into 1 inch cubes, put in a large bowl and sprinkle with salt.
Pat eggplant cubes dry and combine with the other vegetables. Add remaining three tablespoons olive oil, mix well and pour into greased baking pan.
Bake at 420°F (220° C) for 30-40 minutes (depending on your oven. Watch the vegetables closely and stir occasionally, add more olive oil if they seem too dry). The vegetables should become browned but remain somewhat crisp.
Cook pasta according to package directions; meanwhile, in a pan which is large enough for pasta and vegetables to fit in, gently heat the canned tomatoes or passata or tomato sauce, stir in the pesto.
Add roasted vegetables to the tomato-pesto sauce, mix well, then add drained pasta.
Add grated parmesan cheese or pecorino, and serve immediately.