Black Angus beef fillet with warm potatoes in cheese sauce and mushrooms

Preheat oven to 240°C/220°C fan. Cut potatoes into bite-sized chunks.
Halve Brussels sprouts. Place potatoes on a lined oven tray, drizzle with olive oil and season with salt and pepper. Toss to coat, then roast until tender, 20-25 minutes. When the potatoes have 20 minutes remaining, add Brussels sprouts cut side down to the tray and roast until tender.
TIP: The Brussels sprouts will char slightly, this adds to the flavour!
Meanwhile, finely chop garlic. Thinly slice onion and button mushrooms.
In a large frying pan, heat a drizzle of olive oil over high heat. Season premium fillet steak all over, then add to the hot pan. Sear steak until browned, 1 minute on all sides. Transfer to a second lined oven tray. Roast for 8-10 minutes for medium or until cooked to your liking. Remove the tray from the oven and set aside to rest.
While the steak is roasting, return the frying pan to medium-high heat with a drizzle of olive oil. Cook garlic, stirring, until fragrant, 1 minute. Add mushrooms, onion and the butter and cook, stirring occasionally, until softened, 5 minutes. Season to taste, then transfer to a large bowl. When the potatoes and Brussels sprouts are done, transfer to the bowl with the mushrooms and toss to combine. Sprinkle over grated Parmesan cheese.
Wipe out the frying pan, then return to medium heat. Heat cream and crumble in beef stock cube, stirring, until slightly thickened and reduced, 1-2 minutes. Stir through any steak resting juices.
Slice premium fillet steak. Divide steak, Brussels and Parmesan mushroom potatoes between plates.
Spoon over creamy sauce to serve. Enjoy!