Whisk heavy cream and allulose in a medium-large saucepan over high heat, whisking and keeping a close eye on it so it doesn't bubble over, until brown and thickened and has reduced by half. Whisk in vanilla during the last minute.
The caramel will take 10-20 minutes to turn golden depending on the size (width) of your pot and how hot your stove-top is. Once the caramel is golden, turn off the heat and allow to cool for 5-10 minutes before transferring into a mason jar or airtight container.
Store at room temperature for up to 3 days or in the fridge for up to 3 weeks.
Nutritional info is per tablespoon and is less than 1 net carb per serving!