Preheat the oven to 325 degrees Fahrenheit. Put half the cream and all the sugar over the fire and stir until the sugar is dissolved; take from the fire, and, when perfectly cold, add the remaining half of the cream. Freeze the mixture, and add the bananas mashed or pressed through a colander. Put on the lid, adjust the crank, and turn until the mixture is frozen rather hard.
Grate and sift the biscuits. Scald half the cream and the sugar; when cold, add the remaining cream and the vanilla, and freeze. When frozen, remove the dasher, stir in the powdered biscuits, and repack to ripen.
As soon as the custard begins to thicken the saucepan must be taken from the fire and the stirring continued for a second or two longer. If the cooking is done in a double boiler the risk of boiling is very much lessened.
Blanch and pound or grate the nuts. Put half the cream and all the sugar in a double boiler; stir until the sugar is dissolved and stand aside to cool; when cold, add the nuts, the flavoring and the remaining cream, mix, add the coloring, and turn into the freezer to freeze. If green coloring matter is not at hand, a little spinach or parsley may be chopped and rubbed with a small quantity of alcohol.