Adding sprinkles seems like an easy way to decorate a batch of butter cookies or other relatively plain-looking cookies for holiday or some other festive occasion. They’re bright, colorful and, unlike frostings and glazes, need no prep time. But sprinkles can come with their own problems because they don’t always end up where you want them to be; frequently, when you’re applying sprinkles, you end up with more on the baking sheet than you do on the cookies themselves! Sprinkles have a hard time sticking to dough that isn’t tacky enough. For instance, when cookie dough is rolled out on a lightly floured surface, it picks up some flour so that it isn’t sticky and can be handled easily – and that same flour will prevent sprinkles from sticking to the cookies.
There are a couple of simple things that you can do to help those sprinkles stick. The easiest thing to do is to brush the tops of the cookies with a little bit of water or milk, using just enough to dampen the cookie dough and no more. This will help the sprinkles stick and won’t change the finished appearance of the cookie when you’re done baking. You can also brush the cookies with a little bit of egg white, which will provide some adhesive, but will also make the cookies appear a bit darker and shinier. Take a sheet of notebook paper and fold it in half. As for technique, pour the sprinkles down the “channel” to direct them onto the cookies, rather than shaking the container of sprinkles all over the baking sheet to eliminate the mess and waste usually associated with sprinkle-ing cookies.
Finally, if you’re using big, round sprinkles, you’re going to need to press in the sprinkles when you apply them. Large nonpareils, for instance, need to be “anchored” into the cookie dough, or they simply won’t stay put on the trip from the countertop to the oven.