In a small saucepan, add your butter and allulose and place it over medium heat. Once it begins to bubble, stir regularly for 5 minutes.
Reduce the heat to low and add in the heavy cream. Gently stir the mixture and continue doing so until the caramel syrup begins to thicken, around 5 minutes.
Once it has slightly thickened, remove the caramel syrup from the heat. Continue stirring regularly until it reaches room temperature.
Transfer into a jar or bowl and cover, until ready to use.
Notes
One serving is two tablespoons.For salted caramel, add 1/2 teaspoon of salt.TO STORE: Keep the syrup at room temperature, in a sealable jar or bowl. It will keep well for up to 4 weeks. If you'd like to keep it longer, you can store it in the refrigerator for up to 2 months. TO FREEZE: Store it in the freezer for up to 6 months. TO THAW: Let the caramel syrup thaw completely to room temperature.Recipe barely adapted from here.