2 pounds button mushrooms
1 tablespoon olive oil
2 teaspoons chopped fresh thyme leaves
1 tablespoon freshly squeezed lemon juice
Preheat the oven to 500 degrees and put the rack in the lowest position.
Prep the mushrooms: Wipe away any soil or dark spots with a damp paper towel. Remove and toss the stems, then cut the mushrooms in half.
In a large bowl, toss the mushrooms with the olive oil and thyme, then sprinkle them lightly with salt and pepper. On a baking sheet, spread them in a single layer, leaving space between them.
Roast mushrooms on the bottom rack, turning them once or twice by shaking the pan or stirring with a spatula, until the mushrooms are tender and brown in spots, about 12-15 minutes.
Sprinkle with lemon juice and more salt and pepper to taste.