Coffee Ice Cream No. 1

A still-frozen custard ice cream from the era when the new mechanical refrigerator replaced the hand-cranked freezer. The whipped cream is what keeps it from setting into a solid block, so treat it as structural rather than decorative.

• Do not let the custard boilFour eggs in one cup of milk thicken fast. Cook over low heat or in a double boiler, stirring, until it coats a spoon at about 170-175F. A boil scrambles it, and no amount of straining afterward will restore the texture.
• The coffeeA quarter cup of dry ground coffee steeped in scalded milk gives a strong infusion. Use a coarse grind and strain through a fine sieve lined with cheesecloth, or the finished cream will be gritty. Do not use instant here; the quantity is calculated for grounds.
• Whipping the creamTwo cups of cream, whipped to soft peaks that just hold their shape, folded into a fully cooled custard. If the custard is still warm the cream collapses and you lose the aeration that substitutes for churning.
• "Freeze for 5 hours"The recipe calls for no ice and no rock salt, which points to the freezing compartment of a refrigerator, in a shallow tray, without churning. Five hours in a modern freezer may be enough for a shallow tray; overnight is safer.
• Improving the textureStill-frozen mixtures form coarse crystals. Stir the edges into the centre once or twice during the first two hours, or churn the cooled custard in an ice cream machine and fold the whipped cream in at the end.
• Yield and servingRoughly a quart and a half, which makes six generous portions. Let it stand at room temperature ten minutes before scooping; a no-churn custard freezes hard.
• SaltAn eighth teaspoon of salt is a flavour adjustment for the coffee, not part of any freezing brine. Keep it.