Preheat a broiler. Lightly brush the peppers with olive oil. Broil the them until the skins have blackened. Remove from heat and place in a paper or resealable plastic bag to cool, about 30 minutes. Remove the peppers from the bag, and remove the seeds and skins. The skins should peel off easily. Cut the peppers into small pieces. Add peppers, garlic, olive oil, and basil to a skillet and cook for 10 minutes, stirring. Carefully (because it's hot) place pepper mixture in a blender and puree until smooth. Return the puree to the skillet and bring to a boil. Add the half-and-half, and romano cheese. Cook, until the cheese melts, stirring constantly. Add the butter and stir until melted. Simmer for 10 minutes, season with salt and pepper to taste.