In a large bowl add the room temperature butter. Beat with an electric mixer on high for 5 minutes till fluffy and white in color.
Add the powdered sweetener of choice and beat it on the lowest setting for a minute, or until the sweetener is completely mixed in with the whipped butter.
Increase the speed to high and beat for 2 to 3 minutes or till light and fluffy.
Add the vanilla extract and heavy cream and beat again for 1 minute.
Use immediately to frost your favorite favorite keto cakes. Or refrigerate for later.
This frosting can also be frozen for up to 6 months. To use, thaw in the refrigerator overnight, and beat with an electric mixer for couple of minute, till light and fluffy.