Hard boil eggs, 8-10 minutes. Cool quickly by running under cold water, this will prevent yolk from greying.
Once the eggs are cool, carefully peel them. (You can boil eggs a day in advance and leave in fridge overnight, this sometimes makes peeling them easier.)
Peel onion and slice into thin rings. Alternately layer eggs, onion slices and slices of beets into a clean, wide mouth quart jar, packing lightly so not to break the eggs. Add fresh chillies to suit, I usually use about 4-6 of the birds eye variety.
Heat the vinegar, along with half the liquid from the beets and the salt until just boiling. Gently pour over eggs, filling until covered. Add more vinegar if a little short.
Let cool and place in fridge.
For Turmeric Eggs omit beets and add 1 teaspoon each cumin and mustard seeds to jar. Omit beet water and add 1/2 cup water and 1 teaspoon turmeric to vinegar and salt.