Nicholas Biondo/Demand Media

If you've ever been to a hibachi restaurant, then perhaps you've seen the volcano onion trick, also known as the "Benihana onion trick" since this restaurant was one of the oldest to do it. If you haven't been to a hibachi restaurant, or you need something to jog your memory, the onion volcano trick is when the chef builds a triangular shape out of the onions and gets a hibachi fire to go through the top. This gives it the appearance of a volcano, which is very impressive to the diners.

If you have seen this before, you might wonder how it's done so that you can do it at home to impress your friends or even a date. Though the trick is easy to learn, it's important to keep in mind that if it's not done right, it can be dangerous. So, follow the instructions carefully.

Get All the Necessary Materials

In order to do the hibachi volcano trick, you'll first need to go out and buy the right ingredients and materials. Having the right materials ensures that you can do the volcano trick safely:

  • A flat-top grill or a cast-iron skillet

  • Several white, round onions in case you want to practice a few times

  • 80-proof vodka

  • A long-reach lighter

  • A sharp slicing knife or an onion slicer

  • A barbecue fork and hibachi-style spatula (sometimes sold together)

  • Two squirt bottles for the oil and vodka

Prepare the Onion

Once you get home, the first step is to prepare the onion. Peel it well. Then, slice the onion in thick slices at least an inch thick. There are several ways to slice an onion, but remember that you want slices that are thick enough to stack well in the shape of a volcano. Therefore, there's only one way to cut it really well:

  • Cut the onion cleanly in half.

  • Take one half and place it face down on the flat side that has just been cut.

  • Hold the top of the onion firmly and cut side to side to get the thick base slice, which should be about an inch thick. Once you have that, separate it by pushing out a few of the inner layers, keeping a thick, firm outer layer as the base. Keep in mind that each layer will have even more layers of onion within it. Keep those intact.

  • The inner layers of varying thickness should be used as the stacks, so push them out slowly one by one. About five slices total should do.

  • Test the onions to see if they stack well. Set them aside.

Heat the Grill or Pan

Whatever grilling or heating mechanism you're using to make the hibachi flames should be on high heat. Check to see whether or not you have a nonstick surface, and if necessary, grease it with a little bit of cooking oil. Either way, using some oil will help the flame.

Stack the Onion Slices Like a Volcano

When the grill is hot and sizzling, place your volcano onion stack slowly on the grill, using the fork and spatula combination to balance it. If you're having trouble maneuvering the tools, using two forks may be easier.

Though you can use your hands for more control, if you decide to do this, you must be extremely careful because the grill is hot. Make sure the top onion stack has a hole wide enough that it goes straight through to the grill and that you can pour the liquid into it.

Pour a Little Oil Down the Center

If you haven't done so already, make sure you get your cooking oil into one of the squirt bottles. Place the tip into the top hole of the onion volcano and squirt lightly for about two seconds.

Pour a Little Vodka Down the Center

Like the oil, pour some of the 80-proof vodka into the other squirt bottle. For about three to four seconds, squirt the vodka inside the top hole exactly as you did with the oil. Be careful not to drip it elsewhere on the grill, as this can lead to a larger, unintended flame.

Use a Long Lighter to Light the Hibachi Flames

Finally, take your long lighter, hold it close to the top of the volcano and then light it, or light it close to the top and wave it over as it's lit. Make sure to stand far back and keep your face away from the grill to avoid getting burned. The flames should spout through the onions immediately, and it will die down in about a minute, when you will see the smoke coming through.

If the flame does not go out or seems to be getting out of control, extinguish it right away. Do not move the onion slices, as this can just spread the flame.

This trick is safe if you follow the directions, but it is not ideal for those who do not have experience with cooking.