Sauté the aromatics: Heat the olive oil and butter in a large frying pan over medium-high heat. Add the diced onion and cook for 3–4 minutes until it turns translucent and smells sweet. Toss in the minced garlic and cook for another 30 seconds until fragrant—you’ll know it’s ready when the garlic aroma hits your nose.

Brown the mushrooms: Add the sliced mushrooms to the pan in a single layer. Let them sit undisturbed for 2–3 minutes so they develop a deep golden-brown colour. Stir and continue cooking for another 4–5 minutes until the mushrooms are tender and have released their liquid. The pan should look dry and the mushrooms should have a rich, nutty scent.

Add the pasta and stock: Pour in the chicken stock and bring it to a boil. Break the fettuccine in half if needed so it fits in the pan, then add it to the liquid. Stir well to prevent sticking. Reduce the heat to medium and let it simmer for 8–10 minutes, stirring occasionally. The pasta will absorb most of the stock, and the sauce will start to look creamy and thick.

Wilt the spinach: Once the pasta is al dente and the sauce has reduced, add the fresh spinach in handfuls. Stir gently—the spinach will wilt in about 2 minutes. You’ll see the vibrant green leaves soften and darken, and the pan will look lush and inviting.

Finish with cream and cheese: Reduce the heat to low and pour in the double cream. Sprinkle the grated Parmesan over the top. Stir everything together for 1–2 minutes until the sauce is silky and coats the fettuccine evenly. The colour should be a pale, creamy gold, and the smell will be rich and indulgent.

Season and serve: Taste the pasta and add salt and black pepper as needed. Sprinkle with fresh parsley and serve immediately. The sauce should cling to each strand of pasta, and the mushrooms should be tender but still holding their shape.