In a sizable bowl, blend the shredded cheeses.
Mix in mayo and cream cheese till smooth.
Incorporate roasted red peppers.
Season with onion powder, dry mustard, and cayenne pepper. Mix well. For a subtler taste, add dried parsley.
For flavors to blend, refrigerate for at least an hour or overnight.
Stir once more before serving. Garnish with red peppers or parsley if desired
