Step 1

Preheat oven to 450°F.

Step 2

Toss mushrooms, onion, 1 tablespoon oil and 1/8 teaspoon salt in a large bowl. Spread in an even layer on a large, rimmed baking sheet. Roast, stirring occasionally, until soft and golden brown, 15 to 20 minutes.

Step 3

Meanwhile, whisk the remaining 2 tablespoons oil, lemon juice, thyme, 1/8 teaspoon salt and pepper in the large bowl.

Step 4

Remove the mushroom mixture from the oven. Immediately add sherry and garlic to the pan, stirring and scraping up any browned bits. Scrape the mixture into the bowl with the dressing. Add greens and toss to coat. Serve the salad sprinkled with Parmesan.