- Cut eggs in half lengthwise and scoop yolks into the bowl of a standing mixer fitted with paddle attachment. Reserve whites.
- Add goat cheese, mustard, and mayonnaise to yolks in bowl and season with salt and pepper. Mix until smooth. Transfer to a piping bag.
- To serve, pipe yolk into whites, top with a thin piece of prosciutto, some chives, and a few drops of truffle oil.