Preheat your oven to 180ºC/160ºC Fan/Gas 4

Pour the instant cake mix into a large bowl, add three medium eggs, 120ml vegetable oil and 230ml water. Mix until smooth and creamy.

Grease a 20-inch square pan and sprinkle it with cocoa powder. Give the pan a good shake so that it's coated with the cocoa powder this will stop the cake from sticking.

Pour in the cake mixture and bake in the oven for 23-28 minutes or until a skewer inserted into the middle of the cake comes out clean. Leave the cake to completely cool in the pan.

Meanwhile, add a tin of condensed milk to a microwaveable bowl and heat it for around 30 seconds until it's warmed through.

In the microwave, melt 100g of dark chocolate in short 30 second bursts. Once melted, pour the chocolate into the warm condensed milk and whisk until you have a smooth, glossy and pourable sauce.

Once the cake has cooled, use the end of a wooden spoon to poke holes all over it.

Pour half of the sauce into the holes and then set it aside.

Unwrap the small Cadbury Creme Eggs and poke them into the holes. I used two packets of small Cadbury Creme Eggs in total.  It doesn't matter if you have more holes than eggs.

Pour the remaining chocolate sauce on top of the cake and smooth over with a palette knife. Leave to cool.

Whip 450ml of double cream until it has thickened then add 2 tablespoons of icing sugar. Take care not to let the cream curdle. You are looking for a smooth, spreadable consistency the same as buttercream icing: thick enough that it won't slide off the cake.

Using a food processor or rolling pin, crush 5 Oreo biscuits and sprinkle them over the top of the cream.

Decorate with Malteeser bunnies and jelly carrots.