I prefer to start with Instant Pot hard-boiled eggs, but if you don’t have an Instant Pot, you can simply drop room-temperature eggs into rapidly boiling water (12 minutes for chicken eggs and 15 for duck eggs). Remove the eggs from the water and immediately submerge them in an ice bath. Peel the eggs once they are completely cool. Make your brine by adding the vinegar, water, and salt to a saucepan. Bring to a boil, and allow the salt to dissolve completely. Set the brine aside until needed.
Meanwhile, wash your jars well. Choose a flavor variation in the recipe notes below, and add the seasonings to the jars.
Add ½-1 cup brine to eacj jar.
Layer your eggs into the jar, packing them tightly, but not so tight that the whites break or crack.
Pour remaining brine over the eggs until they’re covered completely.
Add lid and refrigerate for 2 weeks.
Enjoy as-is, or in all your favorite recipes.