Bring the above mix (minus the sliced onions) to a rolling boil, then reduce heat to a low boil for 5 minutes. While the brine mix is cooling is the perfect time to get your onions sliced and eggs shelled. Once the brine is cooled, pour the whole mix into a 1-gallon container (sealable glass jar works best, like the big 1-gallon whole-pickle jars) and add the eggs and sliced onions. The eggs and onions may not all sit below the level of the brine right when you put them in, but overnight it should all settle to be covered. Should sit minimum of 6 weeks. Best taste is 6 weeks to 6 months, but since they're pickling, they're edible looooong after that (they just start getting a bit rubbery around 8-9 months). Recipe is scalable, so if you don't have 1-gallon jars, make 1/2 batches... don't make 1 batch & try to divide it among multiple containers as the ingredients settle to the bottom of the kettle.