In a standing mixer, add the flour, forming a well in the middle. Then add the rest of the dough ingredients except for milk into the well. Mix at a medium-high speed, drizzling in enough milk until the mixture forms a ball. Continue for another 5 minutes to knead the dough.

Remove the dough from the bowl of the standing mixer and place it on a well floured board. Using well floured hands, knead the dough ball by hand until perfectly smooth, elastic dough. It should be soft but not sticky.

Cover the dough tightly with plastic wrap and let it rest for 30 minutes.

Divide the dough into halves and roll out each half into a sheet about 3 mm (1/6 inch) thick. [NB: This corresponds to Setting 2 or 3 on most pasta machines.] Cut the sheets into roughly 12-15 cm (5-6 inch) lengths, then cut each resulting sheet into strips no wider than 1 cm (1/3 inch).

Flour the strips well and set on a floured surface until needed.

Place your clams and mussels in a pot, along with a splash of white wine. Cover and simmer over a lively flame just until their shells have opened.

Remove the clams and mussels from the pot and, when they are cool enough to handle, shell them. (You can leave a few unshelled for decoration.)

In a large skillet, sauté the garlic along with the parsley stems (and, if using, the hot red pepper) gently in abundant olive oil until fragrant and just beginning to brown around the edges. Remove and discard the garlic and parsley stems, along with red pepper if used.

Pour in the juices from the clams and mussels, making sure to leave any sediment in the pot. Let the juices cook off until well reduced.

Now add the tomatoes and simmer for a couple of minutes, until they've softened. Add the shrimp and toss just until they cooked through, then add the shelled clams and mussels. Turn off the heat but keep warm.

Bring a large pot of well salted water to the boil. Add the scialatelli and cook until ever so slightly undercooked, 3-4 minutes depending on their thickness.

Transfer the scialatelli to the skillet with the seafood and mix over gentle heat until the sauce clings to the pasta.