Vegetable-Stuffed Rolled Flank Steak
1 flank steak (2 lbs.)
1⁄2 cup red wine vinegar
3 cloves garlic, finely chopped
2 tsp. dried thyme
Kosher salt, to taste
6 oz. baby spinach
4 boiled carrots, halved lengthwise
2 hard-cooked eggs, peeled and
1 small onion, thinly sliced crosswise
1⁄4 cup chopped parsley
2 tsp. chile flakes
1 1⁄2 cups beef stock
2 tbsp. olive oil
1. Arrange steak on a cutting board so that the long side is parallel to you. Using a long knife, butterfly the steak to within 1⁄2" of the far edge so that it opens like a book. Put steak between 2 layers of plastic wrap. With a mallet, pound to a 1⁄4" thickness. Poke steak all over with a fork. Transfer, cut side up, to a baking sheet lined with plastic wrap. Sprinkle meat with vinegar, garlic, and thyme. Cover with plastic wrap; let marinate for 6 hours or overnight in refrigerator.
2. Heat oven to 375°. Arrange meat cut side up so that the grain is parallel to you; season meat with salt and arrange spinach evenly over top. Top spinach with carrots, arranging them evenly so that they run parallel to the grain. Place eggs between rows of carrots and scatter onion rings evenly over top. Sprinkle evenly with parsley and chile flakes and season with salt.
3. Starting with the edge closest to you, roll meat forward to form a tight cylinder. Using kitchen twine, tie the meat at 1" intervals. Heat oil in a 6-qt. oval dutch oven over high heat. Sear meat all over until brown, about 10 minutes. Pour in the beef stock and add enough water that it reaches one-third of the way up the meat. Cover, transfer to the oven, and cook until very tender, about 2 hours. Let matambre cool for 15 minutes. Slice and serve.