These are vintage Hall China Forest Green & White custard cups or ramekins.

These are vintage Hall China Forest Green & White custard cups or ramekins. Manufactured by the Hall China Company, these cups were a common kitchen staple from the 1920s through the 1970s. The heavy, thick-walled design is characteristic of restaurant ware, built for durability. They typically measure about 2.5 inches in height and 3 inches in width. Often marked with a maker's mark and a product number (commonly \#351 or \#352) on the bottom, indicating a 1/2 cup serving size.