1. Combine the porcini and boiling water in a bowl. Let stand for 30 minutes. Remove the mushrooms with a slotted spoon and chop them. Strain the soaking liquid through a fine sieve and reserve. Bring a large pot of salted water to a boil.

2. Heat the olive oil in a large frying pan over medium-high heat. Add the white mushrooms and cook, stirring often, about 5 minutes, until golden. Add the porcini and garlic and cook for 30 seconds. Pour in the porcini liquid, add the bay leaf, and simmer until the liquid is reduced to a glaze. Reduce the heat to low.

3. Add the tomatoes and wine and simmer for 7–8 minutes, until the liquid is slightly reduced and the tomatoes are beginning to break down. Remove the bay leaf. Add the shrimp and cook for 1 minute, or until just opaque. Season with salt and pepper.

4. When the sauce is almost done, cook the spaghetti in the boiling water according to the package directions until al dente. Drain well, then return to the pot. Add the sauce and toss well. Transfer to deep bowls and serve hot.