Ingredients

• 4 large garlic cloves
• 2 teaspoons salt
• 2 tablespoons fresh lemon juice
• 1/2 teaspoon black pepper
• 1/3 cup extra-virgin olive oil
• 1 lb sirloin steak (1 inch thick), trimmed of excess fat
• 2 medium skinless boneless chicken breast halves (1 lb total)
• 1 1/4 lb medium shrimp in shell (31 to 35 per lb; about 40), peeled and deveined
• 1 lb mushrooms, trimmed and halved through stem if large
• Special equipment: about 100 (6-inch) wooden skewers, soaked in water 1 hour

Instructions

1. Mince garlic and mash to a paste with salt using a large heavy knife. Transfer to a small bowl and whisk in lemon juice and pepper, then add oil in a stream, whisking until emulsified. Divide marinade among 4 (1- to 2-quart) bowls.
2. Prepare skewers: Cut steak into 20 to 25 (1/4-inch-thick) slices (about 4 inches long and 1 inch wide), then toss with marinade in one of bowls and thread each slice lengthwise onto a skewer. Cut chicken breast halves diagonally into 20 to 25 (1/4-inch-thick) slices (about 4 inches long and 1 inch wide; if breasts are thin, hold knife at a 45-degree angle to get 1-inch-wide slices). Toss with marinade in another bowl and thread each slice lengthwise onto a skewer. Toss shrimp with marinade in another bowl, then thread 2 shrimp onto each of 20 to 25 skewers. Toss mushrooms with marinade in remaining bowl and thread 2 small mushrooms or 2 large halves onto each of 20 to 25 skewers.
3. Cut steak into 20 to 25 (1/4-inch-thick) slices (about 4 inches long and 1 inch wide), then toss with marinade in one of bowls and thread each slice lengthwise onto a skewer.
4. Cut chicken breast halves diagonally into 20 to 25 (1/4-inch-thick) slices (about 4 inches long and 1 inch wide; if breasts are thin, hold knife at a 45-degree angle to get 1-inch-wide slices). Toss with marinade in another bowl and thread each slice lengthwise onto a skewer.
5. Toss shrimp with marinade in another bowl, then thread 2 shrimp onto each of 20 to 25 skewers.
6. Toss mushrooms with marinade in remaining bowl and thread 2 small mushrooms or 2 large halves onto each of 20 to 25 skewers.
7. Prepare grill for cooking over hot charcoal (high heat for gas); see "Grilling Procedure," below. Grill skewers in batches on lightly oiled grill rack, covered only if using a gas grill, turning over once with tongs, until beef is medium-rare, about 3 minutes total; chicken is just cooked through, about 3 minutes; shrimp is just cooked through, about 2 minutes; and mushrooms are tender, about 4 minutes.
8. Prepare grill for cooking over hot charcoal (high heat for gas); see "Grilling Procedure," below.
9. Grill skewers in batches on lightly oiled grill rack, covered only if using a gas grill, turning over once with tongs, until beef is medium-rare, about 3 minutes total; chicken is just cooked through, about 3 minutes; shrimp is just cooked through, about 2 minutes; and mushrooms are tender, about 4 minutes.
10. Grilling Procedure If using a charcoal grill, open vents on bottom of grill, then light charcoal. When charcoal turns grayish white (about 15 minutes from lighting), hold your hand 5 inches above grill rack to determine heat for charcoal as follows: Hot: When you can hold your hand there for 1 to 2 seconds Medium-hot: 3 to 4 seconds Low: 5 to 6 seconds If using a gas grill, preheat burners on high, covered, 10 minutes, then, if necessary, reduce to heat specified in recipe.
11. If using a charcoal grill, open vents on bottom of grill, then light charcoal. When charcoal turns grayish white (about 15 minutes from lighting), hold your hand 5 inches above grill rack to determine heat for charcoal as follows:
12. Hot: When you can hold your hand there for 1 to 2 seconds
13. Medium-hot: 3 to 4 seconds
14. Low: 5 to 6 seconds
15. If using a gas grill, preheat burners on high, covered, 10 minutes, then, if necessary, reduce to heat specified in recipe.