Heat a non-stick frying pan over a high heat. Add a little oil and, once hot, sear the beef with the garlic for a minute each side. Set aside to rest. Add a little more oil to the same pan.
Preheat oven to 400 degrees. Gently heat 3 tablespoons of oil in a large cast-iron pan. Add the Brussels sprouts, cut-side down, in one layer, and brown in batches. Place in the oven, and roast ...