The best tool for this task is a standard Mason jar ring. It’s almost like they had khanom nang led in mind when they designed these metal rings. Measuring 2 3/8 inches in diameter, a Mason jar ring produces rice cakes that aren’t too big or too small. Besides, the hole in the middle allows you to unmold the pressed cooked rice easily with the back of a spoon. Don’t have a Mason jar ring? An empty tuna can with both ends removed would work as well.