1. Combine the steak, vinegar, onion, rosemary and salt in a heavy duty snap-lock bag. Marinate for at least 30 minutes.
2. Simmer the chickpeas, garlic, flaxseed oil and 3⁄4 cup of the stock in a saucepan for 10 minutes, or until the garlic is very tender. Transfer the mixture to a blender or food processor. Blend, scraping down sides as needed, until smooth. Season with plenty of pepper. Return to the saucepan to simmer over low heat if the mixture is too runny.
3. Place a large non-stick frying pan over medium-high heat. Add the remaining 1⁄4 cup stock to the frying pan and bring to a boil. Add the broccolini. Cook, tossing, for 3 minutes, until the broccolini softens. Remove and cover to keep warm.
4. Wipe the frying pan dry. Add the olive oil to the pan and cook on medium-high. Remove the steak from the marinade (reserving any left for a balsamic sauce). Sear the steak in the heated pan for 3 to 4 minutes, or until it’s browned on the bottom. Flip and cook for 4 to 6 minutes, then remove the pan from the heat. Reduce heat to medium. Remove the steak to a cutting board and let it rest for 5 minutes. Meanwhile, add the remaining marinade to the pan and return it to the heat. Scrape the bottom of the pan to remove the browned bits. Cook at a brisk simmer for 3 to 5 minutes, or until the mixture is sticky. Remove from the heat and set aside.
5. Cut the steak across the grain into thin slices. Spoon the chickpea purée and the broccolini onto 4 dinner plates. Top the purée with the beef, then drizzle the beef with the balsamic sauce. Sprinkle the cheese over the broccolini.
Per serving: 1,203 kJ, 24 g protein, 17 g carbohydrates, 11 g fat (3 g sat fat), 41 mg cholesterol, 420 mg sodium, 10 g fibre, 104 mg calcium