Line a loaf pan with parchment paper and set aside. Roughly chop the mini eggs and use your hands to break up the digestive biscuits.
Add the chocolate chips and butter to a large heat-safe bowl. Warm the chocolate in the microwave in 30 second increments, stirring in between each, until both are melted and well-combined.
Set aside to cool to room temperature so that you don’t melt your marshmallows.
Add the digestive biscuits, chopped candy eggs, and marshmallows to the melted chocolate. Mix until well combined.
Press the mixture into the parchment-lined pan, then top with additional whole mini eggs. Set in the fridge to chill for at least 2 hours.
Once the bar is chilled, slice into pieces. Store in the fridge in a tightly-sealed container for up to two weeks.