Diplomat cream is the professional baker’s tool for pastry cream that won’t collapse and turn watery. It uses both cornstarch and gelatin for the reliable structure, but a little cold butter and whipped cream keep it silky, tender and lightweight. You can fill the shells with this cream up to four hours in advance and not be disappointed.
- 2 cups milk
- ½ cup sugar
- 5 egg yolks
- 3 tablespoons cornstarch
- 1 pinch salt
- 2 tablespoons heavy cream
- 2 tablespoons cold butter
- 1 teaspoon vanilla extract
- 1 teaspoon granulated gelatin
- 2 tablespoons tap water
- ½ cup heavy cream
Scald the milk with half of the sugar (1/4 cup) in a 2-quart sauce pot. Remove from heat.
In a stainless-steel bowl, whisk the remaining 1/4 cup sugar, with yolks, cornstarch and salt until thick and creamy and pale yellow. Whisk the hot milk into the yolk mixture and return the sauce pot to the stove and whisk constantly over medium-high heat until it bubbles and thickens, 60 to 90 seconds.
Remove from heat, pour contents back into the bowl and stir in the vanilla extract. Set bowl over ice bath, and let cool a couple minutes but whisk in the cold butter while the mixture is still warm. When the pastry cream has cooled completely, stir in two tablespoons of cold heavy cream to loosen a bit. Keep chilled over ice bath.
Sprinkle gelatin over the tap water evenly to soften. Break up any clumps, then microwave for 10 or 15 seconds to dissolve completely.
Thoroughly whisk dissolved liquidy gelatin into the stiff and cool pastry cream.
Whip 1/2 cup cold heavy cream to stiff peaks and fold into the chilled pastry cream, blending thoroughly.
Keep chilled until ready to use.
Source : cooking.nytimes.com