Place eggs in a pot and cover with water. Turn to medium-high heat and set a timer for 18 minutes. The water will start to boil about midway through; 18 minutes is used from the start of cooking though – not the boiling point. (As an alternative, you can start to boil and then set the timer for 8 minutes from there).

Meanwhile, while eggs are cooking, place butter in a skillet over medium-high heat. When the butter has melted, add shallots and mushrooms. Cooking for around 7-8 minutes, until the mushrooms are brown and tender.

When eggs are done, run them under cold water or place them in an ice bath. Remove the shells, then slice the eggs in half. Scoop out the yolks into a separate bowl and place the whites on a plate.

In the bowl with the yolks, add the mayo, vinegar, salt, and pepper. Mash everything with a fork until well combined. Stir in the shallots and mushrooms.

Spoon filling into the halved egg whites. Top with chives. Enjoy!