INSTRUCTIONS
1. Bring a large pot of water to a boil over high heat. Soak the dried porcini in 1 cup hot water for 10 minutes. Strain through a fine-mesh sieve, and set both the liquid and mushrooms aside.
2. In a large fry pan over medium heat, melt the butter with the olive oil. Add the garlic and rosemary and sautee until fragrant, about 1 minute. Add the onion and sautee until softened, about 3 minutes. Add the reserved porcini and the fresh mushrooms and cook, stirring frequently, until they release some of their liquid, about 5 minutes. Add the wine, reduce the heat to medium-low and cook until most of the alcohol has evaporated, about 1 minute. Add the tomato paste, reserved mushroom liquid and stock and continue to cook, stirring occasionally, until the flavors have blended, about 10 minutes. Remove and discard the rosemary sprig. Season with salt and pepper.
3. Meanwhile, add 2 Tbs. salt and the pasta to the boiling water. Cook, stirring occasionally to prevent sticking, until al dente, according to the package instructions. Drain the pasta and add to the sauce. Warm briefly over low heat to blend the flavors and serve.
