Red beetroot leave
Nice red veins on the leaves. I think this variety is called Bool's Blood.
Wikepedia's definition:
The garden beet (Beta vulgaris subsp. vulgaris var. vulgaris), also known as the table beet, beetroot, red beet or informally simply as beet, is one of the many cultivated varieties of beets and arguably the most commonly encountered variety in North America and Britain.