In a double boiler, heat the chopped dark chocolate and heavy cream over simmering water. Stir until melted and smooth, creating a luscious ganache.

Remove from heat and stir in the vanilla extract and liqueur if using.

Allow the ganache to cool to room temperature.

Using a spoon or piping bag, fill the silicone molds with the ganache.

Refrigerate the molds for about 2 hours, or until the ganache is firm.

Melt the chocolate for coating using a double boiler or microwave, ensuring it reaches a smooth consistency.

Carefully remove the ganache from the molds and dip each piece into the melted chocolate.

Place the dipped bonbons on wax paper to set and let them cool completely.