Line a muffin tray with paper liners or silicone molds

In a bowl mix peanut butter, powdered sweetener, coconut oil, and vanilla extract

Stir until the mixture becomes smooth and creamy

Spoon a small amount of melted chocolate into the bottom of each liner

Freeze briefly until the chocolate layer sets

Add a spoonful of peanut butter mixture on top of the chocolate layer

Flatten the filling gently

Pour another layer of melted chocolate over the peanut butter

Freeze until the cups become firm

Remove from molds and serve