1) Rub tenderloin with oil, salt, pepper, and rosemary. Cover with cling film and let marinate for 1 to 2 hrs in the refrigerator.
2) Preheat oven to 190C/Gas 5.
3) Heat 2 tbsp olive oil in an oven-safe saute pan over high heat. Sear tenderloin on all sides until nicely coloured all over. Transfer pan to oven and roast for 10 mins or until internal temperature reaches 62C. Let rest for 5 to 10 mins before thinly slicing on the bias. Serve with the risotto and garnish with a sprig of fresh rosemary.For the risotto:
1) Place mushrooms in a bowl and pour boiling water over them; cover and let sit 10 mins.
2) Heat the oil in a large saucepan over medium heat. Add shallots and sweat until they start to turn translucent in colour, just a couple mins. Add rice and stir around until all the grains are covered with oil. To the rice, add the stock and wine. Remove the mushrooms from their liquid, reserving the liquid, and chop them roughly. Add the mushrooms with their liquid to the pot. Add salt, raise heat to medium-high, and bring to a simmer. Stir well, reduce heat to low, cover, and cook for 20 mins, stirring once more after 10 mins. Remove from heat and stir in the butter, pecorino, and parsley. Serve with sliced tenderloin.