Preheat the oven to 350°F. Place a baking sheet in the oven to heat. Meanwhile, bring a large pan of water to a boil and cook the potatoes for 5 minutes. Drain, reserving ½ cup of the water.
In a large bowl, toss the potatoes, carrots, onions and sprouts with 2 tablespoons of extra virgin olive oil to coat. Arrange on a preheated baking sheet, spaced apart. Sprinkle with 1 teaspoon of the dried Italian herbs, pinch of kosher salt and ground black pepper, then roast for 30 minutes. Tossing half way through the roasting time.
Meanwhile, mix 1 teaspoon of the vinegar with the garlic, remaining Italian herbs, 2 teaspoons of extra virgin olive oil,, dijon mustard and plenty of black pepper. Rub some of this over the steak, put in a shallow dish and set aside.
Mix the rest of the marinade with the bouillon and ½ cup of the reserved potato water, then set aside.
Meanwhile, heat a small non-stick frying pan over medium-high heat. Lift the steak out of the marinade, shake off the excess and sear for 2-3 mins on each side until cooked to your liking.
Remove to a board and allow to rest. Pour the gravy mixture into the frying pan and simmer until thickened slightly to make a gravy. Slice the steak and serve with the roast vegetables and gravy on the side.