Preheat your oven to 180°C / 350-375°F / Gas Mark 4-5
Mince the garlic cloves
Combine olive oil, minced garlic, dried thyme, salt and pepper and stir to combine
Use a mandolin to thinly slice some of the mushrooms
Then use a knife to roughly chop the rest
Add all of the chopped mushrooms to a baking dish and use a pastry brush to coat them in the seasoned oil
Pop the butter into the baking dish also and then place the dish on the middle rack in the oven, roast for 15 mins
Bring a pot of boiling salted water to the boil and cook tagliatelle according to packet instructions Note 4
Drain the pasta and keep the pasta water
Make the sauce by combining the cream with the chopped parsley at a low heat in a large flat saucepan
Use an oven mit to remove the mushrooms from the oven and transfer into the cream and parsely, stir to combine
Add the drained cooked pasta to the creamy mushroom sauce, stir to combine. Add a little of the pasta water as needed to thin the sauce
Serve with parmesan cheese, cracked pepper and parsley.