Preheat oven to 375 F. Place red pepper, tomatoes, onion and garlic and celery on a baking tray. Drizzle with olive oil a rub all vegetables to get them covered with the oil. Arrange the tomatoes and bell peppers with the cut-side up. Bake for 45 minutes.
In a soup pan, heat the vegetable broth on medium heat. Add the roasted vegetables (reserve 1 of red bell pepper for garnish). Add all vegetables and simmer for 10 minutes.
In a food processor or blender, add all ingredients from pan as well as tomato paste, salt and pepper and paprika powder. Once all ingredients are blended to a nice puree, add back to soup pan then add parsley. Cook on low heat for another 5 minutes. If you desire a thicker consistency, cook a few minutes longer.
Pour the soup into a bowl and garnish with the reserved roasted red pepper.