Using a small offset spatula, spread a thin, even layer of marshmallow fluff around the top 1″ of the outside of your glass. Sprinkle sprinkles (say that 5x fast) on fluff. Set glass aside.
On a foil-lined baking sheet sprayed with nonstick cooking spray, toast peeps under a broiler, until slightly golden brown. Keep a close eye on them as they can burn rather quickly.
Just as the marshmallows are finishing up, put ice cream and milk in the blender. Combine briefly, then add toasted peeps and blend until incorporated. Add in a few drops of food coloring (same color as your peeps) and blend just until fully incorporated.
Pour shake into a glass and top with some whipped cream. Garnish with Peeps.
*Multiply recipe as necessary for additional shakes, or use smaller glasses.