Soak the bean sprouts in a big bowl of cold water for a few minutes to clean. Remove and rinse a few times in a colander. Set aside.
In a large pan over medium-high heat, add a little oil and the shirasu. Pan fry for about 3-5 minutes, until the shirasu is crisp and slightly golden. Pour onto a plate.
In the same pan, add little more oil and the bean sprouts. Season with the fish sauce. Stir fry until just cooked through. This should only take a few minutes.
Add half of the shirasu back into the pan and gently mix. Then pour everything onto a plate (or shallow bowl).
Sprinkle the other half of the shirasu on top. Eat hot and enjoy! Best with a big bowl of rice.