1.Brush the inside of a 22cm diameter (12-cup capacity) dome-shaped stainless steel bowl with the oil; place in the freezer for 10 minutes.
2.Place the chocolate Melts in a microwave-safe bowl. Microwave on medium (50%) for 2½ minutes, stirring halfway, or until melted.
3.Pour the chocolate into the bowl and turn to coat the bowl, spreading the chocolate to the top edge of the bowl with the back of a spoon to create an even, thick layer. Place the bowl in the freezer for at least 30 minutes.
4.Gently slide the chocolate shell out of the bowl. Fill the shell with easter eggs. Place a serving plate or board on top and gently turn it over.
5.Drizzle the ice-cream coating in a decorative pattern on dome. Decorate with spinkles or Easter eggs before the coating sets.
6.Crack the cake with the back of a heavy spoon, meat mallet or rolling pan to smash open.