Pastry Cream

Pastry cream is a delicious filling used in cream puffs éclairs. You can also use pastry cream to fill crêpes or you can simply eat it alone. This pastry cream is smooth with a pleasant vanilla flavor and a touch of sweetness. Makes about 2 cups.
Ingredients:
2 Cups half-and-half
1/2 cup (3 1/2 ounces) granulated sugar
1/2 vanilla bean, halved lengthwise, seeds removed and reserved. You can also use 1 1/2 teaspoons of pure vanilla extract just add it when you whisk in the butter.
5 large egg yolks
3 tablespoons cornstarch
4 Tablespoons (1/2 stick) unsalted butter, cut into 4 pieces

1. Bring the half-and-half, 6 tablespoons of the sugar, vanilla bean and seeds, and salt to a simmer in a medium saucepan over medium-high heat, stirring occasionally.
2. Meanwhile, in a separate bowl, whisk the egg yolks, cornstarch, and the remaining 2 tablespoons sugar together in a small bowl, whisk until smooth.
3. Whisk about 1 cup of the simmering half-and-half mixture into the egg yolks to temper. Make sure you do it slowly at first and then increase the amount. Then slowly whisk the tempered egg yolks back into the simmering half-and-half mixture. Reduce the heat to medium and continue to cook, whisking constantly, until the pastry cream is thickened and a few bubbles burst on the surface, about 30 seconds.
4. Turn off the heat, remove the vanilla bean and whisk in the butter. (If using vanilla extract add it in with the butter). Strain the pastry cream through a fine mesh strainer to remove any lumps, if desired. Immediately press plastic wrap directly on the surface. Refrigerate the pastry cream until cold and set, about 3 hours.

From: America's Test Kitchen Family Baking Book