Polenta with Roasted Mushrooms

Place racks in upper and lower thirds of over; preheat to 170°. Combine mushrooms, thyme sprigs, and garlic on a large rimmed baking sheet. Season generously with salt and pepper; drizzle with oil. Toss to coat mushrooms, then spread out in an even layer. (Make sure not to crowd the mushrooms on the baking sheet) Transfer to upper rack in over and let mushrooms roast while you prepare polenta

Bring 4 1/2 cups water to a simmer in a large ovenproof saucepan over medium-high heat. Add butter and a generous pinch of kosher salt and wish to melt butter. Gradually add polenta, whisking constantly. (Gradually incorporating the polenta into the water is key to preventing clumps.) Return mixture to a boil, immediately cover pot, and transfer to lower rack in oven. Bake polenta, shaking baking sheet with mushrooms occasionally, until polenta is tender 25-30 minutes

Remove polenta from oven. Crank up oven temperature as high as it will go. Continue to cook mushrooms until crisp around the edges, 5-10 minutes longer

Meanwhile, carefully uncover polenta and whisk vigorously, scraping bottom of pan, until polenta is smooth and thick. Gradually add Parmesan, whisking constantly until melted and incorporated; task and season with more kosher salt and pepper. Cover and keep warm over low heat while mushrooms finish roasting

Remove mushrooms from oven; drizzle with vinegar. Toss to coat; let cool slightly

Divide polenta among bowls and top with mushrooms, thyme leaves, sea salt, and more Parmesan