Preheat oven to 375 degrees.
In a large saucepan, steam the broccoli until fork-tender. In a small saucepan, pour the milk, add the cheese and cook on low heat until melted. Add onion and bell pepper stirring until fully coated. In a large casserole, layer the melted cheese, broccoli and sprinkle with the bread crumbs. Dot the crumb layer with butter and repeat. Sprinkle the final layer with additional crumbs. Cover and bake for 20 minutes; then, uncover and bake for an addtional 5 minutes or until the crumb topping is lightly browned.