METHOD

1. Preheat oven to 220°C (425°F). Place the porcini mushrooms and ½ cup (125ml) of the boiling water in a small heatproof bowl and set aside for 5 minutes to soften. 
2. Heat the butter and half of the oil in a large frying pan over high heat. Add the eschallots and cook for 2–3 minutes or until light golden. Add the garlic and rosemary and cook for 1 minute or until garlic is browned. Add the Swiss, button and chestnut mushrooms, salt and pepper and cook, stirring occasionally, for 3–4 minutes or until golden brown. Add ¼ cup (60ml) vincotto and stir to combine. 
3. Transfer to a large roasting dish. Return pan to the heat, add the stock, porcini mushrooms and porcini cooking liquid and bring to the boil. Add the stock mixture, lentils and remaining boiling water to the roasting dish. Wipe the pan clean with paper towel and heat the remaining oil over high heat. Sprinkle the beef with salt and pepper, and cook for 4 minutes each side until golden brown. 
4. Place on top of the mushroom mixture and cook in the oven for 20 minutes. Reduce temperature to 200°C (400°F) and cook for a further 40 minutes. Brush beef with the remaining vincotto and cook for 5 minutes for medium rare or cooked to your liking. Set aside, covered with aluminium foil, for 10 minutes to rest before serving. Serves 6