In generous saucepot, reduce the one quart heavy cream at a gentle simmer until it is half its original volume.
Meanwhile, in separate, smaller pot, combine clam juice, wine, garlic, peppercorns, salt, dill and vinegar. Reduce at a rolling boil to half its original volumbe, then strain and dispose of garlic and peppercorns.
Add wine reduction to reduced cream and reserve.
With electric mixer, whip 8 oz heavy cream to medium peaks, then add sour cream and whip until blended. (The chef calls this "quick creme fraiche").
In boiling, lightly salted water, cook pasta (if fresh) for 45 seconds or to desired donenesss. Drain in collander and cool by running cold water through it to halt cooking.
In 10-12" sauté pan, heat cream/wine sauce to boil, then whisk in parmesan until well blended. (Sauce will continue to reduce quickly).
Add cooked pasta to sauce and toss to coat evenly. Divide between 4 dishes, topping each with 2 oz smoked salmon, a dollop of creme fraiche and a sprig of dill.Makes 4 to 6