Combine vinegar, water, Cajun spice and optional salt in medium saucepan. Bring to a boil, then simmer 5 minutes.
While brine is simmering, add layer of boiled & peeled eggs to quart jar. Continue adding layers of eggs, alternating between adding jalapenos and garlic to each layer.
Once brine is complete and cooled, pour brine over the eggs, ensuring all eggs are submerged in liquid.
Tighten lid on jar, and store eggs in fridge. Allow at least 2-3 days for eggs to soak up seasoning.