Instructions

1. Finely chop 5 garlic cloves (about 4 teaspoons) and place in a medium bowl. Add 1/4 cup soy sauce or tamari, 1/4 cup Worcestershire sauce, 2 tablespoons granulated sugar, 1 1/2 teaspoons Dijon mustard, 1/4 teaspoon cayenne pepper if desired, and 1 tablespoon of the olive oil. Whisk until the sugar is dissolved.
2. Trim off any large pieces of fat or gristle from 1 1/2 pounds beef sirloin steaks. Cut into 1-inch cubes, add to the marinade, and toss to coat. Cover and refrigerate for at least 2 hours or up to overnight.
3. If using wooden or bamboo skewers, soak 12 in water while you heat the grill. Heat an outdoor grill for direct, medium-high heat (about 400ºF). Let the steak sit out at room temperature while the grill heats.
4. Meanwhile, use a Y-shaped vegetable peeler to shave 2 medium zucchini into wide ribbons: Start on one side of the zucchini, shave lengthwise until you get close to the middle, then flip the zucchini and shave the other side. (You’ll need about 48 zucchini ribbons.) Place in a large bowl and add 1 pint cherry or grape tomatoes.
5. When the grill is almost ready, add the remaining 1 tablespoon olive oil, 1/4 teaspoon kosher salt, and a few grinds of black pepper to the vegetables and toss to combine. Thread the steak and vegetables onto the skewers in this order: Steak, 2 zucchini slices folded like an accordion a few times and threaded through the center, steak, tomato. Repeat the sequence on each skewer and place on a baking sheet.
6. Scrape the grill grates clean if needed. Oil the grill grates with a folded paper towel dipped in olive oil. Grilling in batches if needed, place the skewers on the grill, spacing them at least an inch apart. Cover and grill undisturbed until grill marks appear on the bottom, about 3 minutes. Flip the skewers, cover, and grill until the vegetables are crisp-tender and the beef is at the desired doneness, about 3 minutes more for medium-rare. Transfer to a platter or clean baking sheet and let rest at least 3 minutes before serving.