Probably the same mold as the plaque, circa 1800, pictured in PRATTWARE by Griselda Lewis on page 200, only rather than the typical Pratt colors in that example, this one is decorated with colored glazes---most unusual for this type of ware.

It measures 5 3/8" diameter, and is in great condition, with the exception of a rim chip on the back, which is not at all visible from the front.