Two-Ingredient Frosted Lemonade (Crystal Light)

I needed a Chick-fil-A frosted lemonade fix on a Sunday, which if you know, you know, so I made this Two-Ingredient Frosted Lemonade in the Ninja Slushi instead. Technically three things, but who's counting: water, a Crystal Light lemonade packet and sweetened condensed milk on MILKSHAKE. Comes out creamy and tart like the drive-thru version, way lighter on sugar thanks to the Crystal Light. My kid said it tasted like a lemon creamsicle and demanded a second. Tip: whisk the Crystal Light fully into the water before adding the condensed milk, or you'll get powdery streaks. That's it, that's the whole drink.