Beef tenderloin fillets make this summer dish an incredibly quick standout. You can also use 2 (8-ounce) sirloin steaks, grilled for 4 minutes on each side or until your desired degree of doneness. We simplify the chimichurri formula by leaning on garlic, cilantro, and olive oil. You could also add a pinch of crushed red pepper, ground cumin, and about a tablespoon of fresh lemon juice if you have these ingredients on hand. Parcooked potatoes cook more quickly and evenly on the grill. Instead of microwaving, you could boil the potatoes whole, cool, slice, and refrigerate for later.
Place potatoes in a microwave-safe dish; cover tightly with plastic wrap. Cut a 1/2-inch slit in plastic. Microwave at HIGH 6 minutes or until almost tender. Coat grill grate with cooking spray. Add potatoes to grill (skewer if necessary); cook 5 minutes or until tender and well marked, turning after 3 minutes.
Coat fillets with cooking spray; sprinkle evenly with 1/4 teaspoon salt and 1/4 teaspoon pepper. Add fillets to grill; cook 3 to 5 minutes on each side or until desired degree of doneness. Remove fillets from pan; cover, and keep warm.
Coat squash with cooking spray; sprinkle with 1/4 teaspoon salt and 1/4 teaspoon pepper. Add squash to grill; cook 3 minutes or until tender and lightly charred.
Place remaining 1/2 teaspoon salt, remaining 1/2 teaspoon pepper, cilantro, and garlic in a food processor; pulse until finely chopped. Add oil; process 30 seconds or until smooth. Serve cilantro mixture with potatoes, fillets, and squash.