Eggs:

Hard boil the eggs, then peel them. Allow them to cool to room temperature.

Put them in a jar of Pernicious Pickling's pickled beet brine in the fridge for at least a week.

How much the color soaks into the eggs is related to how "hard" boiled the eggs are and how long they sit in the brine.

Onions:

Blanch onions for 30 seconds, drain and cool.

Add to the jar of beet pickle brine.