Combine 1 cup Lucky Charms cereal (both cereal and marshmallows) with 2 cups milk in a medium bowl, and let soak for 45 minutes. Stir occasionally to keep the cereal soaking evenly. (I know it seems really extra, but the milk truly comes out tasting like cereal and its amazing and delicious.)

Strain the milk into a medium saucepan with a fine mesh sieve. Gently press the cereal to drain completely. (Make ahead: strain milk into an airtight container and store in the refrigerator until you’re ready to use

Sort the remaining 3/4 cup of cereal, and set the marshmallows aside.

Pulse the cereal in a food processor a few times for semi-crunchy crumbs. Avoid over processing, because you don’t want to end up with dust! Transfer to a plate or a wide, shallow bowl.

Next, use your finger or a paintbrush to coat the rim of your mugs with agave nectar or simple syrup. (The syrup may drip down the side a bit, but if you ask me, it adds to the magicalness.)

Dip the rims of the mugs into the cereal crumbs and twist to coat (just like rimming a cocktail!)

Heat the cereal milk over medium-low heat. When the milk begins to steam, use your preferred method of frothing (shake, blend, or wand).

Fill each mug ⅓ of the way with espresso. Use a large spoon to hold back the foam as you fill the mug nearly the rest of the way with warm milk. Use the spoon to top each much with foam, and sprinkle with reserved Lucky Charms marshmallows.