Once upon a time, the word "ketchup" meant more than just thin, sweet, tangy tomato sauce. Ketchup was originally used to describe condiment sauces made from a variety of ingredients, including tomatoes, mushrooms, grapes and apples.
Today's vintage recipe is for one of these alternatives, from Gourmet Magazine, September 1948. Give it a try!
Put 1 dozen peeled, cored, and quartered tart apples into a kettle with enough water to cover them and simmer them until they are soft and nearly all the water is evaporated. Rub the mixture through a sieve and measure the pulp. To each quart of pulp add 2 cups vinegar, 2 medium-sized onions, grated, 1 cup sugar, 3 teaspoons salt, 2 teaspoons powdered cinnamon, and 1 teaspoon each dry mustard and ground cloves. Bring the ketchup to a boil, simmer for 1 hour, and pour it into jars. Seal and store in a dry, cool place.