Line a large baking tray with parchment paper and set aside.
In a large mixing bowl, add the butter and cream until softened and lightened in colour - mix for around 2 minutes.
Add the peanut butter and mix again for 1 minute until combined. Now add the icing sugar and the vanilla and beat on a low speed for 2 more minutes until a crumbly mixture forms.
Measure out 30g portions of the peanut mixture and roll into a ball. Flatten each ball between your palms and use your fingers to narrow one end into an egg shape. The eggs should be roughly 3/4 inch thick. Place the eggs on the lined baking tray.
Chill the shaped peanut butter eggs in the fridge for at least 1 hour and up to 1 day. During the last few minutes of the chilling time, begin melting the chocolate and oil together. I melted my chocolate and oil in a large measuring jug - this is great for dipping later on. Either melt the chocolate in the microwave in 20-second increments, or melt the chocolate in a heatproof bowl, set over a pan of gently simmering water (bain-marie).
Let the warm chocolate sit for 6-8 minutes before dipping. Take the peanut butter eggs from the fridge. Working one at a time, submerge each egg into the chocolate and then carefully lift out using a fork. Tap the fork gently on the side of the bowl/measuring jug to rid of the excess chocolate. Use a toothpick or a second fork to help slide the egg off of the fork and onto the baking sheet.
If you happen to have any leftover chocolate, drizzle it over the eggs. Also, if desired, lightly sprinkle each egg with flaky sea salt or sprinkles while the chocolate is still wet.
Place the eggs back in the fridge for 30 minutes until the chocolate is fully set. The peanut butter eggs will keep stored in the fridge for up to 2 weeks.