How to Make It
Fill a large bowl with cereal, pour the milk in, and stir vigorously. Steep at room temperature for 30 minutes, stirring occasionally.
Finally, you’re allowed to eat the cereal (and remind yourself how magical soggy Lucky Charms is). Reserve ½ cup cereal milk. You could also strain the mixture through a fine mesh sieve, pressing on the cereal to release any extra milk that might have gotten absorbed. Either works.
Dip the rim of your serving glass in marshmallow fluff, coating completely. It won’t look perfect at first and that’s OK. Use your fingers to distribute the fluff evenly and let sit for a few minutes while you prepare the shake. With more time, the marshmallow fluff will melt slightly and drip smoothly along the sides of the glass.
Place reserved cereal milk, vanilla-flavored yogurt, peppermint extract, honey, and green food coloring in a single-serve blender cup. Whirl until the mixture is smooth. Add a handful of ice and blend some more, if you prefer a cold shake.
Pour the copycat Shamrock Shake into your marshmallow-rimmed glass.
Dig through the Lucky Charms box and dish out a handful of clover marshmallows. Stick them onto the marshmallow fluff for a pretty touch and added sweetness to taste.
Serve, and toast to the luck of the Irish.