Step 1

Preheat oven to 220°C/450°F (200°F fan).

Step 2

Toss mushrooms with butter, oil, garlic, salt and pepper in a large bowl using a rubber spatula.

Step 3

Spread on a baking tray and roast for 25 minutes - do not toss or turn.

Step 4

Remove from oven. If using lemon and thyme, push mushrooms together onto one side of the tray, drizzle with lemon, sprinkle with thyme and toss. Serve immediately!

Step 5

(Video here for large mushrooms) Place mushrooms cap side down (ie stems facing up) in a medium baking dish (so they are kind of snug - they shrink).

Step 6

Spoon 1 tsp of butter over each mushroom, then use the rest to brush the edges (or carefully drizzle over edges).

Step 7

Drizzle over olive oil, sprinkle with salt and pepper.

Step 8

Roast for 20 minutes (tender but still a slight firmness) or 25 minutes (tender) - no turning. There will be juices in the pan and plenty pooled in the mushrooms caps.

Step 9

Squeeze over a bit of lemon juice, sprinkle with thyme. Serve mushrooms, drizzled with pan juices (see notes for serving suggestions).