To a saucepan over medium-low heat, add butter and allulose. The butter will melt and will start to bubble, resembling a low boil (do not move on to next step before the mixture is really bubbling and looks like it’s at a low boil). At this point, start a timer to simmer mixture for 3 minutes, stirring a few times with a rubber spatula. You may need to reduce stovetop heat to low to avoid caramel burning. After 3 minutes has passed, pour in heavy cream (you may need to remove pan from heat to avoid it boiling over), then add SunButter, and, optionally, salt.
Whisk ingredients together and then reduce stovetop heat to lowest temperature. Cook mixture until it begins to thicken, which may take anywhere from 7-15 minutes, depending on the room temperature of your kitchen, stirring a few times. Watch mixture carefully to avoid burning.
Meanwhile, while caramel is simmering, to a large mixing bowl, add ice cubes and water to create an ice bath. When caramel has finished simmering, transfer saucepan to sit inside bowl for about 1-2 minutes, depending on the thickness of your saucepan, to stop cooking process. (If you do this for too long, the caramel may split. If that happens, transfer pan back on stovetop over low heat to warm up again, stirring continuously. If you do this, don’t return pan back to ice bath.)
Set saucepan aside and allow to sit at room temperature to thicken, which may take anywhere from 10-20 minutes. It should resemble the thick and sticky caramel that you are familiar with (see photo within blog post for reference, if needed).