Preheat oven to 450°. Place tomatoes in 1 inch deep baking pan, cut side down. Brush tops with ¾ tsp oil. Roast 20-25 minutes or until skins are blistered and charred. Remove and discard skins.
In a 4 qt pot, heat remaining oil over medium-high heat. Add onions, cook & stir until tender. Add garlic & cook 1 minute longer. Stir in broth, orange juice, tomato paste & roasted tomatoes. Bring to a boil. Reduce heat & simmer, uncovered, 45 minutes.
Stir in orange zest, butter, cilantro, honey & salt. Remove from heat & cool slightly. Process soup in a blender until smooth. Return to pot & heat through. Serve.