How to Make It
In a large, nonstick skillet, heat 1 tablespoon of the vegetable oil. Add the diced mushrooms; season with salt and pepper. Cover and cook over moderate heat until tender, 5 minutes. Uncover and cook, stirring, until browned. Transfer the mushrooms to a plate.
In the same skillet, heat another 1 tablespoon of vegetable oil. Add the shallot and garlic and cook over low heat until softened, about 10 minutes. Remove from the heat and stir in the cooked mushrooms.
In a small saucepan, simmer the sugar and water over moderate heat, washing down the side of the pan with a wet pastry brush, until amber, 6 minutes. Add the wine and bring to a boil, stirring to dissolve the sugar. Add the vinegar and boil over high heat until reduced by half, 12 minutes. Stir the mixture into the skillet and cook over moderate heat until the mushrooms are glazed, 3 minutes. Season with salt.
In a medium skillet, heat the remaining 1 tablespoon of vegetable oil. Add the sliced mushrooms, season with salt and cook over moderate heat until tender and lightly browned, about 8 minutes. Stir the mushrooms into the marmalade, and swirl in the butter. Cover and keep warm.
In a medium saucepan, bring the chicken stock to a simmer; cover and keep warm over low heat. In a large saucepan, heat the olive oil. Add the onion and cook over moderate heat until softened, about 5 minutes. Stir in the rice and cook for 2 minutes. Add the wine and simmer until almost evaporated. Pour in about 1 cup of the hot stock, or enough to cover the rice. Cook, stirring constantly, until the stock has been absorbed, about 5 minutes. Repeat, adding 1 cup of stock at a time and stirring until all of the stock has been absorbed. The risotto is done when the rice is just cooked and suspended in the creamy sauce, about 25 minutes. Stir in the butter and season with salt and pepper.
Spoon the risotto into bowls and top with the mushroom marmalade. Shave a few slices of Parmigiano-Reggiano over the risotto, garnish with the herbs and serve.