In a large pot or Dutch Oven, melt the butter with the paprika over medium heat. Add the onion and garlic and cook, stirring, for 3 minutes. Sprinkle in the flour and cook, stirring, for 2 minutes. Stir in the tomatoes. Cook, stirring, until the mixture begins to simmer and thicken. Stir in the bell pepper, chicken broth and sherry. Cover and simmer over medium heat, stirring occasionally, until the pepper is tender, 15 to 20 minutes.