Use this recipe to make our Raspberry Tart. Be sure to make the pastry cream on the same day you plan to use it; otherwise it has a tendency to become thin and runny.
Prepare an ice bath, and set aside. In a medium bowl, combine cornstarch, flour, 1/2 cup sugar, and salt; stir to mix. In another medium bowl, whisk eggs until smooth. Add flour mixture to egg mixture, and whisk to combine.
In a medium saucepan, combine milk and remaining 1/2 cup sugar. Bring mixture to a boil over medium-high heat, stirring until sugar is dissolved. Remove from heat; whisking constantly, slowly pour into egg mixture.
Transfer mixture to a clean saucepan set over medium-high heat. Bring to a boil, whisking constantly, until thickened, about 3 minutes.
Transfer mixture to a large heat-proof bowl. Whisk in butter and vanilla; set bowl in ice bath, stirring occasionally, until completely chilled, 10 to 12 minutes. Cover with plastic wrap, pressing it directly on surface of pastry cream to prevent a skin from forming. Place in refrigerator until ready to use.