For the  Pasta
Put the flour, olive oil, salt and eggs in the bowl of a standing mixer fitted with a dough hook and mix the dough together on medium for 15 minutes.
Press the dough into a round flat disk then in plastic. Refrigerate for at least 30 minutes.
Roll the dough through the widest setting of a pasta machine until the dough is very smooth, it may take up to 10 passes. 
Then continue to roll the dough, each time on a thinner setting until the second to thinnest setting has been achieved.
Cut the pasta sheet on a lightly floured surface, to suit your recipe.

For the Shellfish Pan Sauce
Heat the oil in a pan over moderate heat. Add the onions, garlic, fennel, and pepper flakes to the pan.
Cook the vegetables, stirring often, for 3 minutes.
Add the thyme, tarragon, bay leaf, cream, vermouth and stock to the pan, increase the heat to high and reduce the sauce by half, 10 to12 minutes.
Strain sauce.

For the Ragout
Heat the olive oil in a shallow saucepan over moderate heat.
Add the morels and sautéuntil soft.
Transfer the mushrooms to a plate and set them aside.
Using the setting for either linguine or fettuccine on your pasta machine, cut the fresh pasta, then cook for 3 minutes in a large pot of boiling salted water, or cook the dry pasta until tender.
Drain, return to the pot, and keep warm.
Heat the shellfish pan sauce in a shallow saucepan (you can use the same pan you used to sautéthe morels) over medium-low heat.
Just before serving, whisk in the butter a bit at a time.
Add the tomatoes, fava beans, crawfish, and sautéed morels.

Cook for 2 minutes, and season with salt and pepper.
Divide the pasta into bowls, ladle on the crawfish stew, and garnish with fresh shavings of Parmesan cheese and chervil sprigs.