You don't actually need a pastry bag to pipe these, but it sure makes things handy. This mixture is too thick to pipe from a plastic bag (the usual go-to pastry bag alternative) so make your own with a triangle of parchment paper instead. Here's a great video on how to do just that.
You can use Dutch or natural cocoa in this recipe, they both turn out nicely. The coffee powder is meant to add a little depth to the chocolate flavor, but omit it if you like.
Note: All measurements are in weights, as volume measures can be very imprecise. I strongly recommend using a scale for all pastry projects. Serious Eats' recommended kitchen scale is the Oxo Good Grips Scale with Pull Out Display.
- Yield:makes 1 cup
- Active time: 45 minutes
- Total time:24 hours including dry time
- 5 ounces powdered sugar
- 1 1/4 ounce cocoa
- 1 ounce water
- 1 ounce vanilla extract
- 1/2 teaspoon salt
- 1/4 teaspoon instant coffee powder
Combine all ingredients in a bowl and set a hand or stand mixer set to medium-low; mix until a homogenous paste forms. Scrape the bowl and beaters thoroughly with a rubber spatula and mix for another minute to ensure perfect smoothness. You want to make certain no lumps remain, lest they clog the pastry tip.
Transfer the mixture to a piping bag fitted with either a small plain tip or a multi-opening tip (#134 is a godsend, but #89 and #42 get the job done!). Alternately, transfer the mixture to a homemade paper cone.
Have two sheet pans lined with parchment standing at the ready.
Pipe the sprinkle batter on the parchment in a series of parallel lines. You can pipe the lines pretty close together. Continue piping until you've used up all the mixture.
Set the trays of sprinkle-lines in a safe place and let them dry for 24 hours.
Hold a bench scraper at a 45° angle against the parchment lined sheet pan. Press gently downward and scrape the rows of sprinkles from the parchment. Gather up the lines into a bundle, then use a knife to chop them into sprinkle sized bits, a little shy of a 1/4" long.
Transfer to an airtight container. Sprinkles store indefinitely.