Line a large baking sheet with parchment paper. Set aside.
In a large microwave-safe bowl, melt the white chocolate chips for 30 seconds and then stir. Repeat until smooth and completely melted.
Quickly stir in the marshmallows. Then transfer the mixture to the prepared baking sheet. Use a rubber spatula to spread it out into an even layer (one marshmallow deep).
Put the marshmallow bark into the freezer and chill for 20 minutes.
Remove from the freezer and allow the bark to come up to room temperature. Then, use an egg-shaped cookie cutter to cut the bark into eggs.
Notes
There will be extra scraps left over from cutting out the egg shapes. They can be cut into bite-sized pieces and served in a bowl or in treat bags.