Line a baking sheet with parchment paper or wax paper for easy cleanup.
Place the yellow candy melts in a microwave-safe bowl. Microwave at 50% power for 30-second intervals, stirring well between each interval, until the candy melts are fully melted and smooth.
Using tongs or two forks, dip a Nutter Butter cookie into the melted yellow candy, coating it completely. Allow excess candy melt to drip off, then place the cookie on the prepared baking sheet.
Melt the navy-blue candy melts in a separate microwave-safe bowl, following the same method as the yellow candy melts.
Once the yellow coating has hardened, use a piping bag or a zip-top bag with a small corner cut off.
Pipe the bottom half of each cookie with melted navy-blue candy to create the Minion’s overalls. Place the cookies back on the baking sheet to set.
Add buttons using yellow sprinkles while the candy is still wet.
Melt a small amount of black candy melts using the same method.
Use the black candy melts to pipe on glasses and a smile for each Minion. Place the candy eyes onto the glasses, while the candy is still wet.
Allow all the decorations to harden completely at room temperature or in the refrigerator.
Once fully set, your Minion Nutter Butter cookies are ready to be enjoyed.