Sirloin and Summer-Vegetable Kebabs with Chimichurri

Marinate beef sirloin tips in 2 tablespoons balsamic vinegar, soy sauce, and freshly ground pepper in a shallow dish for 30 minutes. Soak 4 wooden skewers in water. Meanwhile, slice zucchini and summer squash into 1/2-inch rounds. Cut onion into wedges and red bell pepper into 1-inch pieces.

Heat grill to medium-high. Thread beef onto skewers, alternating with vegetables. Grill for 7 to 8 minutes per side. Whisk together parsley, fresh oregano, garlic cloves, extra-virgin olive oil, balsamic vinegar, fresh lemon juice, and coarse salt. Drizzle sauce over kebabs.