Hard boil the eggs.

Loosely chop a head of purple cabbage and place in a large pot (make sure the pot has LOTS of extra room).

Cover the cabbage with water and bring to a boil.

Add vinegar, mix well.

Let simmer appropriately 20 minutes.

Place a strainer or colander inside the pot to push down the cabbage, add eggs inside strainer.

Add a 1/4 teaspoon of baking soda at a time (watch for fizzing overflow!)

Lift the eggs and coat them with the colored foam.

Lift eggs out of the pot fully with tongs and set aside, try not to disrupt the color.