01 - Place two-thirds of the chopped chocolate in a heatproof bowl over gently simmering water. Stir continuously until melted, then remove from heat and stir in the remaining chocolate until smooth.
02 - Using a clean, dry brush or spoon, apply a layer of melted chocolate to silicone or plastic egg molds. Chill in the refrigerator for 10 minutes, then repeat with a second coat. Chill again until fully set.
03 - Heat the cream gently until steaming but not boiling. Pour over white chocolate and stir until fully melted and smooth. Add vanilla extract and butter, stirring until silky. Allow to cool to room temperature.
04 - Spoon or pipe the cooled filling into each chocolate shell, leaving a small gap at the edge.
05 - Cover the filling with a final layer of tempered melted chocolate. Refrigerate until completely set, approximately 30 minutes.
06 - Carefully remove the chocolate eggs from the molds. Store in a cool place until ready to serve.