Toss 1 quart sliced strawberries with 1 tablespoon sugar in a bowl; let macerate 10 minutes. Put 5 egg yolks, 1 egg white, 3 tablespoons sugar, 1 tablespoon marsala wine, 1/2 teaspoon vanilla and a pinch of salt in a large heatproof bowl. Set the bowl over a saucepan of barely simmering water (do not let the bowl touch the water) and whisk vigorously over medium to medium-high heat until thick and creamy, 8 to 10 minutes. Immediately pour over the berries and serve with biscotti.
Photograph by Antonis Achilleos