Brush the steak with half the olive oil then add black pepper if desired. Cover, and leave to sit to one side for at least 20 minutes, or as long as desired.
Meanwhile, add the parsnip and stock to a pot. If the liquid doesn’t cover the parsnip, top up with water. Bring to the boil and cook for 15-20 minutes or until soft and easy to pierce with a fork. Alternatively, you can microwave them on high in a microwave-safe dish for about ten minutes. Strain.
Return the parsnips to the pot with the remaining olive oil. Add the garlic and cannellini beans,then mash. You may need to add another splash of stock to the mash if it’s too dry. Grill the asparagus spears under a medium-high grill for 4-5 minutes or until softened and lightly charred at the tips.
In a non-stick pan over a medium-high heat, cook the steak for 3-4 minutes on each side, or until cooked to your liking. Remove from the pan and leave to sit. Meanwhile, add the lemon juice to the pan, and stir to collect the juices.
To serve, make a bed of the mash and top with the steak and asparagus. Pour over the juice and enjoy.