Place paper cups or silicone molds into a muffin tin for easy shaping.
Gently melt the chocolate using a double boiler or microwave, stirring often until smooth and glossy. The chocolate should be warm but not overheated, with a pleasant aroma filling the kitchen.
Spoon about a teaspoon of melted chocolate into each mold, tilting and swirling to spread it up the sides. Gently tap the tin on the counter to remove air bubbles. Chill in the fridge for 10 minutes to set the base layer.
While the chocolate chills, warm the peanut butter slightly in the microwave for a few seconds until soft and spreadable. Stir in honey and vanilla extract if using, to enhance flavor and smoothness.
Drop small spoonfuls of the softened peanut butter into each chocolate shell, pressing gently to fill the center. Be careful not to overfill—just enough to create a nice, centered filling.
Cover the peanut butter with more melted chocolate, ensuring the filling is completely sealed. Use the back of a spoon or small spatula to smooth the top if needed. Chill again for at least 1 hour until fully set.
Optional: Before the final chill, sprinkle a tiny pinch of flaky salt or crushed nuts on top for extra flavor and visual appeal. Once set, carefully remove the peanut butter cups from the molds and place on a plate.
Let the peanut butter cups sit at room temperature for about 10 minutes before enjoying. This allows the chocolate to soften just slightly, enhancing the melt-in-your-mouth experience. Store leftovers in an airtight container in the fridge for up to two weeks.