Shredded Parmesan cheese or the shredded three-cheese blend of Parmesan, Romano and Asiago can be substituted for the Asiago cheese.
Iceberg lettuce will keep up to one week in the refrigerator. If you plan to use the lettuce within a day or two, remove the core by striking the core end against a flat surface, then twisting the core and lifting it out. Hold the lettuce head, cored end up, under running cold water to separate and clean leaves, then turn it over and drain thoroughly. Refrigerate in sealed plastic bag or a bowl with an airtight lid.