If you look between the FAVORITE and the PIQUA on this old Favorite griddle you will see a ghost mark.
The ghost mark reads "ERIE".
Erie is the name used from 1880 to 1905 or 1906 on the products of the Griswold Manufacturing Co. After 1905/6 the brand would change to Griswold and continue until 1957 as the premier maker of cast iron cookware (or hollow ware as it was called).
Favorite cast iron cookware was produced in Piqua Ohio by the Favorite Stove and Range Co. 1916-1934 is the usually cited era of Favorite hollow ware production.
So how did a Favorite griddle get an Erie ghost mark? They used an Erie griddle as a pattern to create their casting mold. Later Favorite products used their own designs and were superb.
Ghost marking is prized by collectors as these pieces are less common.