This is a Shelley China, England bone china domed covered muffin dish, butter dish or cheese dish in the Dainty shape and Polka Dot pattern 13748/T and turquoise colorway made between 1940-1966.

The lidded muffin dish is 4.5 inches high by 8.25 inches in diameter and both pieces are in excellent used vintage  condition with no chips, cracks or wear.

These muffin dishes are also used as butter or cheese dishes. Lovely and so rarely found in this excellent condition, if you can find one at all!