What does Boxing Day have to do with boxing?
1884, from Russian borshch "cow parsnip," which was an original recipe ingredient. Borscht belt "region of predominantly Jewish resorts in and around the Catskill Mountains of New York" (also known as the Yiddish Alps) is by 1938.
beet soup of the Slavic countries. Although borsch is important in Russian and Polish cuisines, the Ukraine is frequently cited as its place of origin. Borsches are eaten hot or cold; some are clear and light, others thick and substantial.