This rare form is large: 12-1/2" long by 8" wide. The "Curling Palm" pattern is carefully printed in dark blue, and very distinct.
It is in excellent condition, with only a few small nicks to the glaze, and one shallow chip on the back, which is not visible from the front. There are no other chips, no cracks, no crazing, and no repairs. It rings when tapped (as well as earthenware ever does).
The shape can be found in several books. It's on page 97 of Gillian Neale's "Encyclopedia of British Transfer-Printed Pottery Patterns. The one shown there has a fixed butter tub and was made by Wedgwood c. 1810-20. Also see Robert Copeland's "Spode's Willow Pattern", page 52. I have read that Leeds Pottery made this form both with and without the attached butter tub. This dish has a raised platform for a butter tub, and a slight ridge to hold it in place.
The "Curling Palm" pattern is most often associated with Job Ridgway, but several other Staffordshire potters had their own version of the pattern. This dish has no maker's marks of any kind.