Mongole soup was a popular American soup of the 1930s, now largely forgotten, and of uncertain origin. It was typically made by mixing creamed split pea soup with tomato soup, usually both canned, and enriching the result with light cream and dry sherry. If made from scratch, it was made by mixing split pea soup with puréed tomatoes and enriching with cream.
It was popular enough to be a favorite of President Franklin Roosevelt, and is described in The Presidential Cookbook by Victoria Nesbitt (1951).
Cream Mongole Soup
Source: From Joy of Cooking (1946), quoted in Fashionable Food: Seven Decades of Food Fads, by Sylvia Lovegren (2005)
1 15 oz. can condensed tomato soup
1 15 oz. can condensed split pea soup
1 soup can water
1 soup can half-and-half of light cream
2 tbsp. dry sherry
Combine the soups and water and stir to blend. Bring quickly to a low boil and let bubble for a few minutes. (This is done as a precaution against can-borne germs). Remove from the heat and let cool a little. Stir in the half-and-half and heat until the mixture is hot, but do not let it boil once the cream is added. Remove from the heat. tir in the sherry and serve in heated bowls.