pepperoni and broccoli salad recipe

1 pkg (3/4oz) Italian salad dressing mix
1 bunch (approx 1 lb) broccoli
8 oz fresh mushrooms, sliced
1 cup diced Swiss cheese
3 to 4 oz pepperoni, sliced thin
1 medium green pepper chopped

Prepare dressing mix according to package directions; set aside. Trim off large leaves of broccoli. Wash broccoli and break off florets; reserve stalks for use in other recipes. Combine florets, mushrooms, cheese, pepperoni, and green pepper in a large bowl. Pour dressing over salad; toss gently. Cover and refrigerate 8 hours or overnight.