In the bowl of a stand mixer fitted with paddle attachment, place 2.5 pounds cookie mix, 3 oz soft unsalted butter and 6 oz cold water. Mix on 1st speed, scraping down the bowl often until mixture resembles a thick paste and has no lumps. By hand, stir in 2 oz sprinkles. Using a black handled 1 oz scoop, scoop cookie dough onto parchment lined sheet trays (1.4 oz dough pucks). Place in cooler for minimum of one hour. Overnight is optimal. Once dough is completely chilled, place 3 mini marshmallows in the center of each dough puck and wrap dough around marshmallows (pucks finished weight will be 1.5 oz). Bake at 350°F for 10 minutes or until cookies are golden brown around the edges. Place 2-3 marshmallows on top of cookies just before removing from the oven.