The first prehistoric gourmands used fires blocked with stone and probably fueled with dung. However, when it comes to the contemporary cook’s fuel of choice, celebrity chef and author Mario Batali loves wood: “It provides without a doubt the most delicious and unique flavor and is the most versatile heat source.” When asked to describe his ideal flame-based cooking arrangement, he enthuses, “I would have a wood-burning oven, a wood-fired grill, and a six-burner range with a stainless steel plancha (all with natural gas).”
Open-fire cooking, also called hearth cooking, is a modern throwback to those prehistoric times. With nothing more than a standard household fireplace (or fire pit) and a few cast-iron or earthenware pots, its practitioners produce multicourse meals—from soup to dessert—the way people did before the kitchen as we know it was developed. William Rubel, in his book The Magic of Fire (2002), claims that hearth cooking offers a greater range of fire temperatures and that a more “three-dimensional” placement of the cooking vessels can produce dishes with flavors that are stronger, richer, deeper, and more striking. Stovetop or fireplace, each is a step up from the raw diet.
Chef Michael Tusk of San Francisco’s Cotogna restaurant cooks this soup in the glowing embers
Preparation (serves 4)
Start a wood fire in a grill or hearth an hour ahead of cooking time and let it settle into red embers.
Make a cartoccio—a paper packet—in which to cook the onions: Place a 16-by-24-inch piece of parchment paper on top of a similarly sized piece of aluminum foil. Fold the two in half for a 12-by-16-inch rectangle, with the parchment on the interior.
In a small saucepan, melt duck fat or olive oil and toss in the onions.
Fill the cartoccio with the onions. Bury the packet directly in the coals and bake about 20 minutes.
When the outer skins of the onions are nicely roasted, remove the cartoccio from the embers and let cool. Peel off the charred skins and reserve the onions. Place the onion skins in a 2-quart saucepot with stock and bring to a simmer. Remove from heat, cover pot with plastic wrap when cool, and let steep for 30 minutes.
While the skins are steeping, toss together the garlic bulbs, mushrooms, thyme, bay leaves, vinegar, and olive oil. Season mixture with salt and pepper, and place in the center of the cartoccio. Immerse the cartoccio in the embers and bake for 30 minutes. Remove the cartoccio from the embers and discard the bay leaves and thyme. Strain out the onion skins from the broth. Peel and slice garlic, and add, along with the mushrooms and onions, to the broth. Simmer the broth for just a minute or two and season to taste.
Warm four soup bowls in the oven. Place an egg yolk in each bowl and season with the Maldon sea salt and a bit of black pepper. Ladle hot soup into each bowl, making sure to equally distribute the onions, mushrooms, and garlic. Drizzle olive oil into the soup and finish each bowl with shaved pecorino di fossa. Serve immediately with warm grilled bread.