1½ pounds beef sirloin tips, cut into 1½-inch cubes
1 large red onion, cut into bite-size pieces (about 1.5" x 1.5")
1 red bell pepper, cut into bite-size pieces
1 green bell pepper, cut into bite-size pieces
1 yellow bell pepper, cut into bite-size pieces
1 orange bell pepper, cut into bite-size pieces
Instructions
Whisk together oil, Worcestershire, soy sauce, lemon juice, mustard, garlic, brown sugar, and black pepper in a small bowl. Place beef cubes in a large resealable plastic bag. Add marinade and seal bag, pressing out as much air as possible. Marinate, refrigerated, for at least an hour (I let mine soak for about 4 hours).
Remove meat from the fridge and discard marinade. Thread meat, peppers, and onion onto the skewers, alternating meat and vegetables.
Cook kabobs on the grill over medium-high, about 6-8 minutes each (turning once or twice to make sure that they are evenly cooked). Serve warm and enjoy!
Recipe by Tone and Tighten at https://tone-and-tighten.com/marinated-steak-and-vegetable-kabobs.html