In a large bowl, beat together the cream cheese, peanut butter, sweetener, vanilla extract, and heavy cream until well combined and smooth.
Spoon or pipe into 12 popsicle molds and tap molds firmly on counter to release as many air bubbles as you can. Place popsicle sticks in the center of each (wooden sticks are preferable as they stay in the popsicles better).
Freeze 4 hours until firm. Remove from the molds by running hot water over the outside, then gently twisting the sticks until they release. Keep in the freezer until ready to dip in chocolate.
Line a baking sheet with parchment or waxed paper and place in the freezer. Set a heatproof bowl over a saucepan of barely simmering water. Add the chopped chocolate and cocoa butter and stir until melted. Remove from heat.
Dip a popsicle into the chocolate coating about half way, then let excess drip off back into bowl.
When the chocolate is firm, place on the cookie sheet in freezer and repeat with the remaining popsicles.