The more cream in an ice cream recipe, the less it needs to be cooked.
The recipe on this card is the minimum proportions for an ice cream base that isn’t cooked before being frozen–equal parts milk and cream. Compare this cooked version from the February 2, 1847 edition of the Elyria (Ohio) Courier:
Lemon or Vanilla Ice Cream — Take two drachms of vanilla or lemon peel, one quart of milk, the yolks of three eggs, half a pound of sugar and a pint of cream, beat the eggs well with the milk, then add the other ingredients, set it over a moderate fire, and stir it constantly with a silver spoon until the cream will adhere to it.
The cream will be richer if it is made of a greater proportion of cream, or it may be made of cream alone, sweetened and flavored.
From the box of A.D. from Lutz, Florida, by way of Pennsylvania in the 1940s, and originating in Ohio in the 1920s.
Take one quart of milk and one quart of cream. Sweeten and flavor to taste. Let stand in the freezer for 15 minutes before commencing to freeze.