The CWI Cookbook

 Beet greens
Salt pork, beef or ham
Vinegar or butter (see recipe)

Young beets the size of a pencil, make, with the exception of asparagus the best greens; the leaves must be examined for fear of insects, and well washed; boil with salt pork, beef or ham; the latter is preferable; drain free from water, and serve with vinegar. They may be boiled without pork, and buttered.

The Housekeeper’s Encyclopedia by Mrs. E. F. Haskell 1861

Comment: Beets are one of those double-decker vegetables treasured by many people as much for their leaves as for the root which is the beet itself. As Mrs. Haskell indicates though, the best greens are those of the very young and skinny beets, which if left alone will spend the summer getting plumped up to the size we expect of these tubers. They are often eaten in combination with their close relatives, mustard greens, collard greens or spinach.