The type of sprinkle matters! What to use: Cylinder sprinkles (what I used) or confetti sprinkles. Cylinder sprinkles, also known as Jimmies, are the classic sprinkle most people think of. These won’t dissolve much and won’t lose their color when baking, which is what we want. Similarly, you can use confetti sprinkles which are the flat, circular kind. These will spread their color slightly, but not lose it (these actually result in a much more colorful cookie).  What not to use: Round sprinkles (nonpareils) because their color will rub off and you’ll have crunchy, unpleasant pearls in your dough. Also avoid using sugar crystal sprinkles. These will lose all of their color and result in a gray cookie dough.