Cut bell peppers in half; remove and discard seeds and membranes. Place bell pepper cups in a lightly greased 13- x 9-inch baking dish.
Whisk together polenta and next 5 ingredients in a large saucepan over medium heat; bring to a boil. Cook, whisking constantly, 5 to 7 minutes or until polenta thickens. Stir in cream and next 4 ingredients, blending well.
Spoon mixture into pepper cups.
Bake at 400°for 25 to 30 minutes or until peppers are tender. Garnish, if desired.