Using the largest (and widest) whisk you have, beat cream, sugar, vanilla, and salt in a large chilled bowl until soft peaks form, 3–6 minutes, depending on how many breaks you take.
Do Ahead (chef’s tip section): Whipped cream can be made 2 hours ahead. Cover and chill. Just before serving, whisk cream once or twice to refluff, but don’t over whip it.
To make the berries and assemble
Combine berries, sugar, and salt in a medium bowl. Let sit, tossing occasionally, until juicy, at least 15 minutes.
Add berries to whipped cream and fold gently until mixture is streaky but barely combined (just one or two strokes should do it). Scoop into small glasses.
Notes
Chefs Tip: Whipped cream can be made 2 hours ahead. Cover and chill. Just before serving, whisk cream once or twice to re fluff, but don’t over whip it. Berries can be macerated 2 hours ahead. Leave at room temperature.