01 -
Mix olive oil, soy sauce, lemon juice, Worcestershire sauce, mustard, garlic, salt, and pepper together in a bowl.
02 -
Pour the mixture into a zip-top bag, add beef cubes, and toss to coat. Seal the bag and refrigerate for 10 minutes.
03 -
Prepare the grill to a high heat, ready for grilling.
04 -
In a large bowl, pour boiling water over the mushroom caps and let stand for a few minutes. Drain and set aside.
05 -
Thread the marinated beef and mushroom caps alternately onto skewers.
06 -
Grill the skewers over hot coals for 5-7 minutes with the lid down. Turn the skewers and grill for another 5-7 minutes with the lid up.