In a small sauce pan or non-stick frying pan, turn the heat on to medium and add your butter. Whisking often, cook it until it starts to get bubbly (~3min).

From there it will start to turn a golden brown colour, keep whisking but once it turns a slightly deeper brown (without burning it) remove it from the heat and continue to whisk it while adding in your 1/4 cup heavy cream.

Turn the heat to low and place the pan back on the burner, whisk until the mixture starts to thicken slightly. Then remove from the heat again and mix in your sweetener, vanilla extract, xanthan gum and salt.

At this point, you can shut the burner off and just continue to whisk everything together off the burner until it becomes thick. Once thickened, use a spatula to scrape it into a small bowl and set aside to cool. Then use immediately OR place in the refrigerator covered until you want to use it for up to 5 days.

Right before you use this caramel sauce, give it a good stir with a spoon to bring everything back together (sometimes the butter wants to separate a little). This also thickens the caramel sauce even further making easier to work with (of course if you don't add xanthan gum you won't have to worry about it thickening more, stirring it will just help bind everything back together).