Line a tin (20 cm square tin ) with grease proof paper and place to one side.
Place the condensed milk, chocolate and butter into a microwave safe bowl and place in the microwave for 3 x 30 second intervals, stirring the mix well each time.
Continue to melt the mix in the microwave at 10 second intervals until the mix has completely melted and is smooth. (This should only take another 30 seconds).
Sieve half of the icing sugar into the bowl and mix thoroughly with an electric whisk).
Add the second half of the icing sugar (again sieved) along with ⅔rds of the Cadbury mini eggs and Smarties eggs.
Tip/pour the fudge into the lined tin and gently push to the sides making it as smooth on top as possible.
Sprinkle the surface with the remaining Cadbury mini eggs and Smarties eggs.
Chill in the fridge for at least 1 hour until set, then cut it into squares.