Place the eggs in a pot of cold water and bring to a boil. Once boiling, turn off the heat, cover, and let sit for 12 minutes. Transfer to an ice bath to cool, then peel.

Slice the hard-boiled eggs in half lengthwise. Gently remove the yolks and place them in a medium mixing bowl. Set the whites aside on a clean plate.

Prepare three small bowls with 1 cup warm water, 1 tsp white vinegar, and several drops of food coloring in each (purple, green, yellow). Drop egg white halves into the colored water and soak for 2-5 minutes. Remove, pat dry with paper towels.

Mash the yolks with a fork until crumbly. Add mayonnaise, Dijon mustard, apple cider vinegar, Cajun seasoning, salt, and pepper. Mix until smooth.

Fill the dyed egg whites with the yolk mixture using a spoon or piping bag. Garnish with extra Cajun seasoning and fresh parsley or chives. Serve chilled.