Porcini-Braised Onions

Instructions

1. Preheat oven to 425°F.
2. If onions need to be peeled, bring a large saucepan of water to a boil over high heat; boil onions, 1-2 minutes. Transfer to a colander with a slotted spoon; rinse with cold water, then peel (reserve cooking water).
3. Put mushrooms in a 1-cup liquid measuring cup; pour reserved boiling water from onions over mushrooms, filling the cup. Let sit until softened and cooled, about 20 minutes. Lift mushrooms from liquid; chop finely and reserve liquid.
4. Toss onions with oil, salt, and pepper; place in a 10-inch cast-iron skillet or similar size baking dish. Tuck thyme springs in with onions; roast, shaking skillet several times until browned in spots and starting to soften, about 30 minutes.
5. Add chopped mushrooms and broth to skillet; carefully pour in reserved mushroom liquid, leaving any sand and grit behind in cup (it should be about ½ cup of liquid). Bring to a simmer over medium heat; return to oven. Cook, stirring once or twice, until most of liquid has been absorbed and onions are very soft, 20-30 minutes. Remove thyme sprigs; serve garnished with fresh thyme.