For a rich and creamy caramel flan, try using 5 egg yolks & 2 whole eggs, and only about a cup of water. Avoid creating bubbles when you mix the eggs, water, & condensed milk. Just make sure the eggwhites are blended in.
Another secret to a creamy flan is using a fine meshed strainer. Use this strainer when pouring the mixture in the caramelized flan.