While pie and tart pans come in innumerable sizes, the most common pie pan, and the one used in this book, is 11 inches in diameter from top edge to top edge, leaving about 9 inches of diameter in the middle. Tart pans are harder to standardize. Assume a recipe uses a 9-inch tart pan, unless otherwise specified—this book is filled with tarts made in irregular sizes. A less expensive alternative to a tart pan is a tart ring, which is simply a metal ring that you set on a sheet pan. The sheet pan provides the base for the tart.