Place the eggs in a saucepan and cover with cold water.

Bring the water to a boil over medium-high heat, then cook for 1 minute.

Cover the saucepan and remove it from the heat.

Let the eggs stand in the hot water for 10 minutes.

Drain the eggs and immediately cover them with ice and cold running water to stop the cooking process.

Peel the cooled eggs carefully.

Finely chop the peeled eggs.

Place the chopped eggs in a bowl.

Add Dijon mustard and mayonnaise to the bowl with the eggs.

Stir to combine the egg mixture, mustard, and mayonnaise.

Season the egg mixture with salt and pepper to taste.

To serve, place a rounded teaspoon of the egg mixture on each digestive biscuit.

Top each biscuit with a small amount of black caviar.

Garnish with freshly chopped chives.