For the pasta:
Place the measured flour on a large wooden board (or very large bowl, if you prefer). Create a well in the mound of flour and crack the eggs into the center. Gently beat the eggs with a fork to blend; then use the fork to start stirring and adding flour from the center of the well out and mix well.
You will need to continue pushing the outer well wall of flour up against the center to keep it contained, this can get a bit messy but soon the dough will come together.
When about half the flour is mixed in, start kneading the dough with the palms of your hands and continue to incorporate the remaining flour. Once the dough is together and holding its shape, set aside and scrape up the bits of dough and extra flour off your board.
Knead the dough for 8-10 minutes until elastic and a bit sticky. Form into a ball and place in a bowl and cover with plastic; allow to rest for 30 minutes (at room temperature.)
Slice a small section of dough, flatten with your hands a bit and set your machine to the first level of medium thickness and roll dough evenly into a sheet. Set your machine to the next level to create a thinner sheet, be careful to feed the sheet slowly so it rolls cleanly at this thinner stage (check your machine settings to see how the levels work before you begin, mine has numbered levels on a round dial).
Lay the rolled sheets of dough on a clean covered table and allow to dry for a minute or two before rolling into the fettuccine shape. Dust them lightly with flour so they do not stick together.
When all the sheets are rolled and have dried a bit, stack two to four of the long rolled out noodles together and using a very sharp knife cut the pasta into approx. 3/4 inch wide strips. This hand cut style or "maltagliati pasta" cut is supposed to be irregular and uneven so do not try to be perfect here!
Note: Watch this Italian chef's video on hot to make this hand cut pasta: https://www.youtube.com/watch?v=T2mYG-sI-pg
For the roasted salmon and pasta sauce:
In a medium stock pot, add the vegetable stock, a few garlic slices and a good pinch of saffron threads and bring to slow boil. for about 15 minutes or so. Taste and adjust seasonings (add a bit of sea salt and pepper), remove from heat and set aside.
Take a large baking sheet place your salmon fillet, skin side down and add some of the sliced leeks, shallots and slices of garlic on top. Season with sea salt and pepper and garnish with 2 to 3 fresh lemon slices. Drizzle lightly with olive oil and place in a preheated 400 degree oven.
Roast for about 12-14 minutes depending on the thickness of your fillet (I check the doneness at the 10 to 12 minute mark; remove or put back into the oven if needed for a few more minutes.)
Remove from oven and let rest, loosely covered in foil to keep warm (Note: you can quickly rewarm the salmon before serving if needed; be careful not to overcook at this point.)
Clean and trim the heads of fennel, remove the stalks and fronds from them and set aside for garnishing. Split one fennel in half and thinly slice about 1/2 to 3/4 of the fennel and place in a large bowl.
In a large skillet, drizzle some olive oil and add a small pat of unsalted butter, allow to melt and add in chopped leeks, shallots and remaining sliced garlic and allow to sauté until fragrant.
Once the leeks and garlic have softened a bit, add in the fennel slices from one fennel (reserve the remaining fennel slices for topping the dish) and sauté a bit, season with some sea salt and pepper. Once this is softening add in the glass and wine and allow this to deglaze and cook down until most of the liquid has evaporated. Remove from heat and taste for seasonings; set aside.
Place a large deep stock pot to boil and add sea salt to the water. Once the water comes to a boil, add the fresh pasta noodles from earlier and cook quickly until tender and done (this takes just a few moments as fresh pasta cooks very fast.) Reserve some of the pasta cooking water in a bowl and once the pasta is cooked remove from heat and drain well.
Toss the cooked pasta into the skillet with the cooked leeks, shallots and fennel. Place on medium low heat and stir gently. Ladle in some of the seasoned vegetable stock until the pasta is lightly coated (you can also add some of the reserved cooking water to thicken the sauce a bit.)
Saute this gently until most of the stock is absorbed and remove from heat. At this point add in a large spoonful of the plain greek yogurt and mix gently into the cooked pasta (I kept mine pretty light, but you can add more yogurt (by the spoonful) here if you wish.)
Place some of the finished pasta in each plate; using a fork, flake off individual servings of the roasted salmon and place on top of the cooked pasta. Add some of the fresh sliced fennel to the side of the pasta and top with a healthy dollop of greek yogurt and a generous sprinkle of fennel fronds to taste.
Season with more sea salt and pepper if desired and serve immediately.
Note: I added more of the seasoned stock to my plate as I love a somewhat soupy feel at the bottom of the bowl, so I suggest placing the vegetable stock on the table along with the greek yogurt for you and your guests to customize your own plates before eating.