1: Take the onglet steaks out of the fridge 30 minutes before you intend to cook, to bring them to room temperature. Drizzle the steaks with the olive oil and season with salt and pepper.
2: Heat a medium non-stick frying pan over a high heat. When it is smoking hot, place the steaks in the pan and cook for 2–3 minutes on each side, depending on their thickness. You want to get a deep brown crust on each side and the steaks should still be springy to the touch.
3: Take the pan off the heat and add the butter to it. Baste the steaks with the melted butter for 2 minutes, keeping the pan off the heat. Transfer the steaks to a warmed plate, spoon over half of the pan juices and set aside to rest in a warm place.
4: Meanwhile, place the frying pan back over a medium heat, add the shallot and sauté for 2 minutes. Stir in half the green peppercorns along with the brandy and simmer until the liquor is totally reduced. Now pour in the beef stock and simmer until it is reduced by half. Add the Worcestershire sauce, mustard, herbs, spinach and half of the cream. Stir well until the spinach is wilted.
5: Transfer the sauce to a small food processor and blitz until smooth. Pour this back into the pan and add the remaining green peppercorns and cream. Stir well over a medium heat for 1 minute and then remove from the heat. Pour any resting juices from the steak plate into the cream sauce and stir well. Season with salt and pepper to taste.
6: Carve the onglet steaks into thick slices. Spoon some sauce onto each of 2 warmed serving plates and pour the remaining sauce into 2 small jugs. Lay each sliced steak on the pool of sauce. Serve at once, with the extra sauce, thick chunky chips and/or green beans.
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