Bring a large pan of water to the boil and cook 350g Everyday Value penne as instructed on the pack.
Meanwhile heat 1tbsp oil in a frying pan and cook 250g sliced mushrooms and 1 sliced red onion for a few minutes over a high heat until softened and crisp at the edges.
When the pasta is cooked, drain, reserving a little of the cooking water. Toss with the mushrooms and onion mixture along with 150g grated cheddar cheese and a small handful snipped chives. Loosen with a little of the water if needed.