Sift the a cup of the powdered sugar into a large bowl then add the corn syrup, vanilla if using, then add 1 1/2 tablespoons of water and beat until smooth. You can add more water a teaspoon at a time if needed.
Once smooth sift in the remaining 1/2 cup of powdered sugar and mix until combined. The final consistency should be thick but pipeable.
Divide the icing into batches if you're making different colored sprinkles then mix in food coloring until the desired color is reached.
Transfer to piping bags either fitted with 3, 4, or 5 tips, or with the tip snipped off then pipe lines onto a sheet of parchment paper and set aside to dry out overnight.
Once dry you can cut the sprinkles into pieces and store in an airtight container until ready to use.
To pipe straight lines keep the tip half an inch above the paper; squeeze and pull forward.
Add a bit more food coloring than you think you need. The sprinkles will fade a bit as they dry.
No piping tip? No Problem! Just snip the tip off of a plastic sandwich bag or roll a piece of parchment paper into a piping bag.
This is a great activity to do with kids. If little ones are helping you in the kitchen just have them break the sprinkles with their hands instead of using a knife. It's more fun and safer.
You can easily double this recipe for a larger batch. The sprinkles keep for quite a while so it's nice to have some on hand.