Start by spreading the beef with the yeast extract. Heat the olive oil in a griddle pan, pop in the rosemary or thyme, followed by the beef and quickly pan-fry on high heat to brown on both sides. Transfer the beef to a baking tray and continue to cook in the oven for 5-7 minutes or to your liking. Next, in the same pan add in the garlic and butter and saute for 3-4 minutes. Add in the mushrooms and brown, then splash in the wine to evaporate. Continue to cook for a few minutes until the mushrooms are soft. Next, prepare the mash by heating up the milk in a pan till warm with the butter, salt and pepper. Add in the mashed potato, stir well and continue to heat till thick and smooth. Remove off the heat and stir in the Parmesan cheese. To serve, spoon the creamy Parmesan mashed potato onto 2 serving plates. Slice up the cooked beef and lay on top. Finally, top with the cooked mushrooms and drizzle over any juices.