Chocolate Ice-cream

Glace au chocolat (French chocolate ice cream) teaches one true thing before you touch a pan: smooth frozen custard begins with heat controlled to the degree. Chocolate gives the base depth and body, but the yolks give it its fine texture, and once they enter the saucepan the mixture must thicken without boiling.

The original formula assumed a full quart of milk and an attendant turning a sorbetière packed with ice and salt. Here its quantities are halved exactly for a standard home ice-cream machine, including the unusual half yolk, because a one-quart batch freezes more evenly and leaves room for expansion. The brigade's hand-turning and elaborate moulding were scaffolding, so they can go. Dissolving the grated chocolate in water, infusing the milk with vanilla, cooking the yolk custard, and chilling it completely are the dish, so they stay. One cook, one stove, one evening.

The finished glace is dark, dense, and satiny rather than cream-heavy, with vanilla rounding the chocolate instead of announcing itself. The moment that decides it comes at the custard pan: cook à la nappe, until it coats the spoon, then stop before the first bubble.