1. To make the puree, position the broiler rack 6 inches from the source of heat and preheat the broiler. Cut the top and bottom from the bell pepper to make “lids.” Slice the pepper lengthwise and open it up. Cut out and discard the ribs and seeds. Place the opened pepper with its top and bottom, skin side up, on the rack. Broil until the skin is blackened, about 8 minutes. Transfer to a bowl and cover. Let stand for 10 minutes. Remove and discard the blackened peel. Puree the red pepper and adobo sauce in a blender, adding more adobo to taste. Transfer to a small bowl, cover, and refrigerate until ready to use. (The puree can be made up to 5 days ahead.)

2. To make the bisque, heat the butter in a soup pot over medium heat. Add the onion, carrot, and celery and cover. Cook the vegetables, stirring occasionally, until they are softened, about 5 minutes. Stir in the garlic and cook uncovered until it gives off its aroma, about 1 minute. Add the squash and stir well. Add the broth and rice and bring to a boil over high heat. Reduce the heat to medium-low. Cover and simmer until the squash is very tender, about 25 minutes. Season with salt and pepper to taste.

3. In batches, in a blender with the lid ajar, puree the vegetables and broth and transfer to a warmed soup tureen. (Or use a handheld immersion blender to puree in the pot.) Serve in individual bowls, drizzling the red pepper puree over each serving.