For custard: In a medium saucepan, stir together the 1/3 cup sugar, the cornstarch, and salt. Stir in milk. Cook and stir until thickened and bubbly. Cook and stir for 2 minutes more. Gradually stir half of the hot mixture into egg yolks; return to remaining hot mixture in saucepan. Cook and stir until bubbly. Cook and stir for 2 minutes more. Remove from heat. Stir in marsala, sherry, or orange juice. Transfer to a medium bowl; cover surface with plastic wrap and chill about 2 hours, without stirring, until completely cooled.

Meanwhile, for syrup: In a small saucepan, combine the water and the 1/4 cup sugar. Cook over medium heat until boiling, stirring to dissolve sugar. Boil for 1 minute. Remove from heat; stir in orange liqueur. Cool.

In a chilled small mixing bowl, beat 1/2 cup of the whipping cream with chilled beaters of an electric mixer on medium speed until soft peaks form. Gently fold into cooled custard.

To assemble: In the bottom of a 2-quart souffle dish or trifle dish, arrange about one-third of the cake slices, cutting to fit as necessary. Drizzle with about one-third of the syrup. Spoon about half of the custard over cake; sprinkle with half of the raspberries. Repeat cake, syrup, custard, and raspberry layers. Top with remaining cake slices and drizzle with remaining syrup. Cover and chill for 3 to 4 hours.

Just before serving, beat remaining 1/2 cup whipping cream and the 1 tablespoon sugar until soft peaks form. Spoon on top of cake layer. Sprinkle with chocolate shavings and, if desired, additional raspberries. Makes 8 servings.