Place eggs in a large pot and cover with water. Bring to a gentle boil over medium heat. Cook for about 10 minutes. Transfer the eggs to cold water immediately. Let them cool completely before peeling carefully.

Add vinegar, water, sugar, salt, garlic, beet slices, onion, mustard seeds, peppercorns and bay leaf to a saucepan. Stir well and bring everything to a light simmer. Cook for about five minutes until the flavors blend nicely.

Carefully peel the cooled eggs under running water. This helps remove stubborn shell pieces easily. Try not to tear the egg whites. Smooth eggs look better and absorb the pickling liquid more evenly.

Place peeled eggs into a clean mason jar. Add cooked beet and onion slices around the eggs. Slowly pour the warm pickling liquid into the jar. Make sure the eggs stay fully covered with liquid.

Allow the jar to cool at room temperature for about 20 minutes. Seal tightly with the lid. Place the jar in the refrigerator. Chill for at least two days before eating for the best flavor.

Remove the eggs from the jar when ready to serve. Slice them in half or enjoy whole. The eggs will have a beautiful pink color and tangy flavor that gets stronger over time.