Chocolate Parfait

This is a still-frozen parfait in the older sense: sweetened whipped cream, no churning, no eggs. The whole thing hinges on temperature control at one point.

• Cool the chocolate base fullyThe chocolate-milk-sugar mixture must be cold, or at most barely tepid, before the cream goes in. Warm base thins the cream and it will never whip. Adding the cream slowly at the start, as directed, is what keeps it smooth rather than grainy.
• Baker's Premium No. 1This was plain unsweetened chocolate, sold in cakes scored into squares of one ounce each. Three squares is 3 oz unsweetened chocolate, chopped. Do not substitute semisweet or the sugar quantities go out of balance.
• The sugar is deliberately vagueA cup goes into the base, then "enough sugar to make quite sweet" at the end. Freezing mutes sweetness noticeably, so the unfrozen mixture should taste slightly too sweet. Add the extra to taste, sifted in so it dissolves in the cold cream.
• "Stiff as for Charlotte Russe"That means firm peaks that hold their shape when the beater is lifted, not the soft billowy stage. Under-beaten, the mixture is liable to separate as it freezes into a fatty layer and an icy one.
• Ice and salt, or a freezerPacking a mould in a bucket of crushed ice and coarse salt was the usual domestic way of freezing a dessert like this when it was written; the salt lowers the melting point of the ice so the brine falls below 32F. A covered loaf pan or metal mould in a modern freezer does the same job, though it will want four hours or more rather than two.
• Cream then and now"Heavy cream" of the period was not standardised and may well have been richer than today's 36 percent carton. Modern heavy cream works, though the result may be a little lighter; whip it cold and stop the moment it holds.
• Yield and servingA quart of cream whipped roughly doubles, so allow a mould of at least 2 quarts; it will serve about 10 to 12. Unmould onto a chilled plate and let it soften a few minutes before slicing.