Place eggs in a large saucepan and cover with cold water by 1 inch. Bring to a boil over medium-high heat, then cover, remove from heat, and set aside for 8-10 minutes. Drain, cool in ice water, and peel.

In a large saucepan, combine water, sugar, vinegar, salt, turmeric, mustard, mustard seeds, and cloves if using. Bring to a boil over high heat, stirring until the sugar dissolves.

Reduce heat to low and simmer the mixture for 5 minutes, then remove from heat.

Layer the peeled eggs and sliced onions in a large glass jar or divide between smaller jars.

Pour the warm pickling mixture over the eggs and onions, ensuring the eggs are completely submerged. Seal the jar with a tight-fitting lid.

Refrigerate the pickled eggs for at least one week before consuming, gently shaking the jar daily to evenly distribute the flavors.