In a large bowl, combine the unsweetened coconut cream, powdered sweetener, vanilla extract (if using), and heavy whipping cream. Mix well with a whisk until the sweetener is fully dissolved and the mixture is smooth.
Carefully pour the creamy mixture into popsicle molds. Ensure they are filled evenly. Place the filled molds in the freezer for a minimum of 8-10 hours, or preferably overnight, until completely solid.
To remove the frozen bars, briefly submerge the bottom of each mold in warm water for a few seconds. Gently pull the bars out and place them on a baking sheet lined with parchment paper. Return the baking sheet to the freezer for an additional 30 minutes to firm up again.
While the bars are refreezing, prepare the chocolate coating. In a microwave-safe bowl, combine the sugar-free chocolate chips and coconut oil. Microwave in 30-second intervals, stirring well after each interval, until the chocolate is fully melted and smooth. Be careful not to burn it.
Transfer the melted chocolate mixture into a wide-mouth mason jar or a deep glass. The container should be deep enough to allow an ice cream bar to be fully submerged.
Working quickly, take one frozen bar from the freezer. Dip it into the melted chocolate, rotating the jar or bar to ensure all sides are evenly coated. The chocolate should harden almost instantly.
Place the dipped bar back onto the parchment-lined baking sheet. If desired, immediately sprinkle with chopped nuts or other keto-friendly toppings before the chocolate sets completely. Repeat the process with the remaining bars. Serve immediately or store in the freezer.