Preheat oven to 350° . Prepare Knorr® Rice Sides™ - Cheddar Broccoli with water and Spread according to package directions.
Meanwhile, brown ground beef in 10-inch skillet over medium-high heat; drain. Stir into hot rice. Generously fill each pepper with rice mixture.
Arrange stuffed peppers in 13- x 9-inch baking dish. Bake covered 20 minutes. Remove cover and continue baking 10 minutes or until peppers are tender. Sprinkle, if desired, with shredded cheddar cheese.