From America’s Test Kitchen, re: stabilizing whipped cream:
There are many methods for stabilizing whipped cream. Adding dissolved gelatin, cornstarch, powdered egg whites, meringue powder, cream cheese, and instant vanilla pudding were among the recommendations we found. Other sources suggested exchanging the standard granulated sugar for confectioners’ sugar or for corn syrup. On the wilder side, marshmallows (soaked in the cream or melted) were touted as a stabilizer thanks to their gelatin. Using our standard whipped cream amounts—1 cup cold heavy cream, 1 tablespoon granulated sugar, and ½ teaspoon vanilla extract—we tried each method and refrigerated the various whipped creams for 24 hours.
We’re happy to report that one of the easiest solutions—replacing the granulated sugar with confectioners’ sugar—proved our overwhelming favorite. You’ll need 1½ tablespoons confectioners’ sugar (as opposed to our usual 1 tablespoon granulated sugar) per cup of cream for the proper texture and sweetness. The small amount of cornstarch in the confectioners’ sugar helped produce a silky, weep-free cream, with none of the pastiness of cream stabilized with pure cornstarch.
THE BOTTOM LINE Confectioners’ sugar is our new go-to for fluffy, lightly sweetened stabilized whipped cream.