Rice is notoriously difficult to cook perfectly, even for those with some cooking experience.

So when you double a recipe, you have to account for that evaporation when cook it.

Of course, you could always just spring for anice rice cookertoo.

Surprising and Delicious Foods You Can Make in a Rice Cooker

Science: The Secrets of Cooking Rice - The Cause of Recipe Failure is Not What You Might Think| YouTube