Preheat oven to 400°. Mix first 4 ingredients. Place vegetables in a large bowl; toss with oil mixture. Transfer to a 15x10x1-in. pan coated with cooking spray. Roast vegetables until softened and lightly browned, 45-50 minutes, stirring once., Transfer to a food processor; cool slightly. Add tomato paste; pulse just until blended (mixture should be chunky)., Transfer to a bowl; cool completely. Serve with baguette slices or crackers.