Place eggs in a medium saucepan and cover with cold water.
Bring water to a boil, then immediately remove from heat.
Cover and let eggs sit in hot water for 10–12 minutes.
Transfer eggs to a bowl of cold water to cool, then peel.
Slice eggs in half lengthwise. Remove yolks and place in a bowl.
Mash yolks with mayonnaise, Dijon mustard, salt, and black pepper until smooth.
Fill the hollowed egg whites with the yolk mixture.
Sprinkle with Cajun seasoning.
Cover and refrigerate until ready to serve.