Junket Custard

A rennet-set milk pudding, thickened without eggs or heat. Everything depends on hitting the right milk temperature and then leaving the cups absolutely alone.

• Temperature is the hingeLukewarm means about body heat, 98-100F. Rennet works best near that temperature; milk much hotter than a hand can comfortably hold will give a poor set, and the enzyme is inactivated by heat well before boiling. An over-warmed pan risks sweet milk that never firms.
• Do not disturb itStir the tablet and sugar in quickly, pour at once, and then leave the cups untouched. Moving or stirring the milk once the curd begins to form breaks it and the custard weeps whey instead of setting smooth.
• Junket tabletsThese are rennet tablets, still sold for cheesemaking and puddings, though no longer a supermarket staple. Tablet strength varies a good deal between brands, so check the package rather than assuming one tablet per quart, and crush it so it fully dissolves in the water.
• The milk mattersUltra-pasteurized and UHT milk will not set properly with rennet; the high heat treatment interferes with the way the enzyme coagulates the casein. Use ordinary pasteurized whole milk. Skim milk sets, but weakly and thinly.
• Setting time"Warm room" means 10 to 30 minutes at ordinary room temperature. It is done when the surface holds a clean line if you tilt a cup. Chill only after it has set; refrigerating early stalls the enzyme.
• SweetnessFour tablespoons of sugar to a quart is restrained by dessert standards. A grating of nutmeg on top is a traditional finish.
• YieldSix small cups, about 5 oz each. It does not keep well past a day; the curd continues to tighten and drain.