Soak bamboo skewers in water (prevents the skewers from burning)- at least 30 minutes.
Marinate: Get a plastic containers with lid or a plastic bag and place the chicken, Japanese long onion (negi ねぎ) and mushrooms inside . (Sometimes, I like to marinate them chicken and the onions separately from the mushrooms as the mushrooms like to soak up all of the oil but you can do it all together if you wish). Add the olive oil, garlic powder, basil, white pepper, bay leaves You may need more oil on mushrooms as they marinade. Marinate for at least 30m minutes of up to overnight.
Pre-heat grill :You can use a traditional Yakitori grill as pictured below or any regular grill you have available. (If you have teenage boys like I do , trust me you want a bigger grilling surface)
Place your meats and vegetables on the skewers. Put your marinated mushrooms on the grill. If the mushrooms are very dry just brush with a little extra oil before putting on the grill. I like to alternate and place a chicken cube, a Japanese scallion and then another chicken cube on the skewers.
Pour yourself a little sake, beer or Umeshu (Japanese plum liquor) to enhance the grilling experience.
Start grilling the skewers on medium heat and occasionally turn and spritz with mirin or white wine. Grill for about 3 minutes per side or total about 6 minutes or until the chicken juices run clear. The mushrooms take a little less time to cook (about 4 mins) and I do not turn them but instead leave them with the underside face up so all the delicious juices stay in the mushroom. Salt to taste whilst grilling.
Serve Negima Yakitori with Grilled Portobella hot with Japanese dry pepper shichimi if you wish for a little zest. Enjoy Yakitori as a light snack with some sake, beers or umeshu (plum wine) with friends and family. Or as a full complete meal with some white rice and edamame on the side.
(Hint: If you have teenage boys make sure you stash some of the delicious skewers for yourself before you take them out to the main table or you will be left high and dry as these treats go fast)