Pulse 1 pound trimmed and coarsely chopped strawberries, 12 ounces raspberries, 3 tablespoons of the granulated sugar, 1 teaspoon of the vanilla bean paste, and ⅛ teaspoon kosher salt in a food processor until finely chopped and saucy, 10 to 15 (1-second) pulses. Taste and pulse in more granulated sugar 1 teaspoon at a time as needed.
Beat 1 cup cold heavy cream, 1 cup cold crème fraîche, the remaining 2 tablespoons granulated sugar, and the remaining ½ teaspoon vanilla bean paste together with the whisk attachment in a stand mixer on medium speed until soft peaks form, 2 to 4 minutes. (Alternatively, whisk in a large bowl by hand.)
Divide the fruit mixture evenly between 4 to 6 cocktail glasses, then top with the whipped crème fraîche.
