01 - In a large bowl, whisk together soy sauce, olive oil, balsamic vinegar, Worcestershire sauce, minced garlic, brown sugar, smoked paprika, black pepper, and dried thyme until well combined.
02 - Add the steak cubes to the bowl and toss to coat thoroughly. Cover and refrigerate for at least 2 hours, up to 8 hours for maximum flavor absorption.
03 - Prepare your grill to medium-high heat, approximately 400°F to ensure proper searing.
04 - Thread the marinated steak cubes, red bell pepper, yellow bell pepper, red onion wedges, and mushrooms alternately onto the skewers, distributing ingredients evenly.
05 - Place kebabs on the preheated grill and cook for 10 to 15 minutes, rotating every 2 to 3 minutes, until steak reaches desired doneness and vegetables display light char marks.
06 - Remove kebabs from heat and let rest for 5 minutes to allow juices to redistribute, ensuring tender, juicy results.