1 T cornstarch
6 C milk
1+1/2 C sugar
4 eggs
1/2 t salt
4 C whipping cream
1 T pure vanilla extract

Mix cornstarch to a thin, smooth paste with a little of the milk. Combine with 4 C of the milk and all the sugar, and cook in top of double boiler over boiling water, with occasional stirring, for 20 minutes. Remove from heat. Beat eggs until light colored; gradually stir into the hot mixture and return to heat. Cook 2 minutes longer, stirring constantly. Cool, pour through a strainer into your ice-cream-maker's canister, and add the remaining ingredients, stirring well. [If you want to throw in crushed fruit or other extras, now's the time.] Once the lid's on the canister, follow your usual ice-rock salt-cranking routine.