Begin by boiling sliced beets in a saucepan filled with water, vinegar, salt, and whole peppercorns over medium heat. Allow the beets to simmer for about 30 minutes until they are tender. Once cooked, drain and cool the beets.

After the beets have cooled, take the hard-boiled eggs and gently submerge them in the beet mixture. Let the eggs soak for 2 to 4 hours in the refrigerator, turning them occasionally for an even stain.

Once the eggs are ready, carefully peel them and slice each egg in half lengthwise. Scoop out the yolks into a mixing bowl and mash them with a fork. Add mayonnaise, Dijon mustard, lemon juice, and cold butter to the yolks. Mix until the filling is smooth and creamy.

Fill the stained egg whites with the creamy yolk mixture using a spoon or piping bag. Aim for a generous mound for each, creating a delightful presentation.

Add your chosen garnishes like crispy bacon, fresh chives, or capers atop each filled egg to enhance flavor and visual appeal.