Coat a 9 x 13 baking dish with cooking spray, set aside.
In a large microwave safe bowl, melt the butter. Add in the marshmallows and microwave until just softened, about 90 seconds. Stir in the Rice Krispies cereal until combined.
Scoop about ⅓rd of the Rice Krispies mixture into the bottom of the baking dish. Use a spatula or damp hands to flatten. Spread the Cadbury Mini Eggs over the Rice Krispies layer, saving a few for garnish. Spread on the remaining Rice Krispies mixture and smooth to flatten.
To prepare topping, microwave the melting chocolate according to package instructions until just melted. Stir in the desired amount of green food coloring. In a separate bowl, toss the shredded coconut with a few drops of green food coloring until the desired shade is reached. Spread the green melted chocolate overtop of the Rice Krispies and then sprinkle on the coconut flakes. Garnish with the remaining Cadbury Mini Eggs, sprinkles, or any other desired toppings.
Notes
Marshmallows: mini or full-sized marshmallows work here, just make sure you have 6 ounces of them.
Melting chocolate: I like to put a layer of the chocolate on top of the Rice Krispies so that the shredded coconut sticks better to it. You can use melted white chocolate chips, or even regular chocolate chips.
Cadbury Mini Eggs: these little eggs are an Easter favorite! If you can't find them, you can use Robin Eggs, or any small egg-shaped candy you like.
You can make these up to two days in advance. Just store in an airtight container until ready to serve.