Melt butter in a large saucepan over medium-high heat; add bell pepper and onion, and sauté 3 to 4 minutes or until tender. Add flour, and cook, stirring constantly, 2 minutes. Gradually add broth, and cook, stirring constantly, 4 minutes or until thickened. Reduce heat.
Stir in cheese and next 4 ingredients. Simmer, stirring often, 10 minutes. Stir in half-and-half, and simmer, stirring often, 5 minutes or until thoroughly heated. Garnish, if desired.