Place the chopped dark chocolate in a heatproof bowl.
Gently melt the chocolate using a microwave in 20-second bursts, stirring in between, until smooth and glossy.
Spoon about a teaspoon of melted chocolate into each paper-lined muffin cavity, spreading it up the sides to create a thin shell.
Chill the tray in the refrigerator for about 10 minutes until the chocolate is just set and firm.
In a small bowl, stir the peanut butter with honey or maple syrup until smooth and slightly runny.
Drop a small spoonful of the peanut butter mixture into the center of each chocolate shell, pressing down gently to flatten.
Cover the peanut butter with another teaspoon of melted chocolate, sealing the filling inside.
Chill the tray again in the fridge for 20-30 minutes until the cups are shiny and fully firm.
Once set, gently remove the peanut butter cups from the muffin tin and peel away the paper liners.
For a finishing touch, sprinkle a tiny pinch of sea salt on top of each cup before serving.
Enjoy your homemade peanut butter cups at room temperature or chilled, savoring the rich, creamy filling with a crisp chocolate shell.