Preheat oven to 400 degrees F.
Place the bell pepper, onion, garlic, zucchini, and olive oil in a medium mixing bowl and toss until the vegetables are coated. Spread the vegetables evenly on sheet pan lined with foil and place to the oven. Roast, tossing occasionally, until they are soft and are beginning to turn brown around the edges, approximately 45 minutes. Remove from the oven and cool completely.
Place the vegetables in the bowl of a food processor along with the cream cheese and process until well combined and spreadable; do not process until completely smooth.
Taste and season with salt and pepper, if desired. Spread on soft bread, such as challah, foccacia, or pita bread. Store in the refrigerator in an airtight container for up to 1 week.
Recipe courtesy of Alton Brown, 2004