Prepare icing by dividing and coloring with food coloring.
Assemble decorating bags with couplers and tips, fill with icing, and close tightly with rubber bands. Set aside.
Line a baking tray with parchment paper.
Spray your bowls and spatulas with non-stick spray for easy treat making.
Place the Rice Krispies in a greased bowl.
In a saucepan, start to melt the butter and add the marshmallows and white chocolate over medium-low heat.
Heat, stirring, until most of the marshmallows have melted. Remove from heat, and stir well, using the residual heat to fully melt the mixture.
Pour over the cereal and combine well. Transfer to the baking tray.
Spread the mixture evenly about ¾-inch thick and a rough circle about 10-inches in diameter. SEE NOTES BELOW for a larger batch that fills the baking tray.
Let set about 2 hours. Cut out ovals. (You should get about 22.)
Pipe icing designs on the eggs and let set well, 4 hours to overnight.
Notes
Find recipes for royal icing or sugar cookie icing in the blog post, or use your favorite icing. Alternatively, purchase tubes of cookie icing at the grocery store. For a large batch of Easter eggs (30 to 35 eggs), find how-tos in the blog post to fill the entire baking tray with the cereal mixture.