Preheat oven to 200 C / 400 F.
Thoroughly wash the mushrooms, rubbing to remove any caked on soil. Drain well in a colander then slice thinly.
Lay the mushroom slices out in one layer on a parchment lined baking sheet, drizzle on the oil and sprinkle on the black pepper and salt.
Roast in preheated oven for an initial 20 minutes - drain if necessary and use a fork to flip each slice over.
Roast another 20 minutes or until evenly golden brown - add more oil or roast a bit longer if necessary.
When the mushrooms are about 5 minutes away from being perfectly browned, sprinkle over the sliced garlic clove and fresh thyme. Roast another 5 minutes or until perfectly crispy.
Remove from oven and garnish with more fresh garlic and thyme to serve. Best enjoyed hot.
