בטרסקוץ' סירים דה קרם

Put oven rack in middle position and preheat oven to 149°.

Bring cream, muscovado sugar, and salt just to a simmer in a small heavy saucepan over moderate heat, stirring until sugar is dissolved.

Bring water and Demerara sugar to a boil in a 2-quart heavy saucepan over moderate heat, stirring until sugar is dissolved. Continue to cook, stirring occasionally, until browned and bubbly, about 5 minutes.

Remove from heat and carefully add cream mixture (mixture will bubble up and steam), whisking until combined.

Whisk together yolks and vanilla in a large bowl, then add hot cream mixture in a stream, whisking.

Pour custard through a fine-mesh sieve into a 1-quart glass measure. Skim off any foam with a spoon.

Divide custard among ramekins. Arrange ramekins in a small roasting pan and bake in a hot water bath

, uncovered, until custards are set around edges but still tremble slightly in centers, about 40 minutes.

Transfer ramekins to a rack with tongs and cool to warm or room temperature. Pots de crème will continue to set as they cool.

*Available at specialty foods shops and Dean & DeLuca (800-999-0306).

Custard can be made, but not baked, 1 day ahead and chilled, covered, in glass measure.