Grease a waffle maker with non-stick cooking spray and preheat to a medium temperature.
Use a food processor to grind up the Lucky Charms cereal.
Add the cereal to a mixing bowl with the flour, baking powder, sugar, egg, milk, butter, and vanilla.
Mix just until the ingredients are combined.
Add a couple drops of green food coloring, if desired, and stir to incoporate.
Spoon the batter into the preheated waffle maker.
Cook waffles until they start to turn golden brown and are cooked through and fluffy, about 4-5 minutes.
Serve with whipped cream and Lucky Charms marshmallows.