How to Make It
In a large saucepan, combine the milk with the vanilla bean and seeds and 3/4 cup of the sugar. Bring to a simmer, stirring to dissolve the sugar. Remove from the heat, cover and let stand at room temperature for 1 hour. Discard the vanilla bean.
In a large bowl, whisk the egg yolks with the cornstarch and the remaining 1 cup of sugar. Whisk in 1 cup of the milk mixture. Whisk the egg mixture into the milk in the saucepan and cook over moderately high heat, stirring constantly with a rubber spatula, until the custard just begins to thicken, about 4 minutes. Switch back to a whisk and cook, whisking constantly, until the custard is very thick and bubbling, about 4 minutes longer. Transfer the custard to a large heatproof bowl. Let cool, then press a sheet of plastic wrap directly onto the surface. Refrigerate until chilled, at least 3 hours or overnight.
Preheat the oven to 350°. Butter a 12-by-17-inch rimmed baking sheet and line the sheet with parchment paper. Butter the parchment and dust it with flour. In the bowl of a standing electric mixer fitted with the whisk, beat the eggs with the sugar at medium-high speed until the mixture is thick and pale, about 7 minutes. Beat in the orange zest.
In a small bowl, whisk the cake flour with the cornstarch and salt. Working in two batches, sift the flour mixture over the beaten eggs and fold it in. Pour the cake batter onto the prepared baking sheet and smooth the surface with an offset spatula. Bake in the center of the oven for about 20 minutes, until the cake is golden and springy. Let cool on a wire rack.
In a small saucepan, combine the Marsala with the sugar and bring to a simmer, stirring to dissolve the sugar. Let cool.
Run the blade of a paring knife along the sides of the cake and invert the cake onto a work surface. Peel off the parchment paper. Cut the cake into 3-inch squares. Reserve any scraps to patch holes. In a large glass trifle bowl, arrange a layer of cake squares. Using a pastry brush, soak the cake with some of the marsala syrup. Top with a 1-inch layer of the pastry cream. Repeat with the remaining cake, syrup and pastry cream, ending with a layer of cake and syrup. Cover the trifle loosely with plastic wrap and refrigerate for at least 3 hours or overnight. Top the trifle with the whipped cream and berries and serve.