In a deep bowl, whip the very cold heavy cream using an electric mixer until it begins to thicken.

Add the keto sweetener, vanilla extract, a pinch of salt, and the half cup of frozen berries to the cream. Continue whipping until the ingredients are combined and the cream becomes thick.

Pour the mixture into a freezer-safe container. Place the container in the freezer for 4-6 hours, or until completely firm.

For a creamier texture, you can take it out every hour and stir it with a spoon before returning it to the freezer.

Serve the ice cream frozen, garnished with a few berries before serving.