In a large glass bowl, whisk together the egg yolks and sugar. Split the vanilla bean in half lengthwise and scrape the seeds with the back side of a pairing knife. Add vanilla bean seeds to the egg yolk mixture and whisk to combine. Add wine, a little at a time, and whisk to combine. Add a pinch of salt and whisk again.

Set bowl over a pan of simmering water and whisk vigorously and constantly until the sauce is thick and fluffy, about 10 minutes.

Preheat the broiler.

Place 1/2 cup berries in the bottom of 6 shallow individual gratin dishes or ovenproof bowls. Spoon an even amount of the sabayon over each dish. Sprinkle the remaining berries evenly over the dishes. Place the dishes on a sheet pan and place on the top shelf of the oven under the broiler. Broil until the sabayon is golden brown, about 1 to 2 minutes. Sprinkle with powdered sugar and serve immediately.