Roast beef with cheesy smashed potatoes and rich chanterelle cream sauce

Method

1. Take the beef out of the fridge about 30 minutes before cooking. If using dried chanterelles, cover with warm water and soak for about 30 minutes, or until completely soft. Follow the packet instructions if they specify a longer time. Skip soaking for fresh chanterelles. Heat the oven to 150°C conventional.
2. Peel the carrot and cut into small pieces. Peel and roughly chop the onion. Peel and lightly crush the garlic cloves. Pat the beef dry with kitchen paper and season all over with the salt and black pepper.
3. Heat the rapeseed oil in a frying pan and add the butter for the beef. Brown the meat all over, about 5–7 minutes in total.
4. Place the oven bag in a roasting dish. Add the beef, carrot, onion, garlic and thyme. Pour in the cooking fat from the pan if desired. Place the tip of an oven-safe meat thermometer in the centre of the thickest part of the beef. Close and vent the bag according to the packet instructions, leaving room for it to expand without touching the oven walls or heating elements.
5. Roast in the middle of the oven to your preferred doneness. Start checking the temperature after about 20 minutes and use the thermometer as your guide. After resting, aim for about 58–60°C for pink beef or 68–70°C for well done. Remove the beef a couple of degrees before the desired final temperature, as it continues to rise during resting. Cooking time depends on the thickness and starting temperature of the meat.
6. Cook the potatoes while the beef is in the oven. Scrub them and leave the skins on. Place in a saucepan, cover with water and add salt. Bring to the boil and simmer for about 20–25 minutes until completely tender. Drain and leave to steam-dry for about 5 minutes.
7. Gently flatten the potatoes with the base of a glass or a potato masher to about 1½–2 cm thick. Place in a single layer in the air-fryer basket or on its tray and top with the cheese. Wait until the beef is cooked before air-frying.
8. For dried mushrooms, discard the soaking water, drain, gently squeeze out excess moisture and chop into small pieces. Heat the butter for the mushrooms and fry over a medium heat for about 3–5 minutes, until excess liquid has evaporated and the mushrooms begin to colour. For fresh mushrooms, clean and chop them, cook in a dry pan until the released liquid has evaporated, then add the butter and fry until lightly browned.
9. When the beef is ready, carefully open the bag and lift out the meat. Rest for about 10 minutes, loosely covered. Strain the roasting juices for the sauce, reserving the carrot and onion to serve if desired.
10. Meanwhile, air-fry the potatoes at 200°C for about 10–12 minutes until the cheese has melted and turned golden. Check towards the end. Cook in batches if they do not fit in a single layer.
11. Add the strained roasting juices, cream, milk, Worcestershire sauce and soy sauce to the fried mushrooms. Bring gently to the boil, then simmer uncovered for 5–10 minutes, stirring occasionally. Taste and add the concentrated stock a little at a time, up to 1 tsp.
12. If the sauce is too thick or strongly flavoured, add water 1 tbsp at a time. To thicken it, mix the cornflour with the cold water. Stir in half the slurry first and simmer for 1–2 minutes, adding the remainder if needed.
13. Slice the beef thinly across the grain. Serve with the cheesy smashed potatoes, chanterelle cream sauce, and the carrot and onion from the oven bag.