Lemon Cream Sauce
Measure flour onto work surface or into large bowl. Make well in centre; crack eggs into well. Add salt to eggs. With fork, beat eggs, gradually incorporating flour around edge of well, until soft ragged dough forms. Knead until smooth, about 5 minutes, adding more flour if necessary to prevent ball from sticking. Wrap and let rest for 30 minutes. (Make-ahead: Refrigerate for up to 2 days; bring to room temperature before using.)
Cut dough into quarters. Shape each into a flat rectangle. Feed through widest setting on pasta machine until smooth, about 5 times, each time folding dough in half either lengthwise or crosswise. Roll out to progressively thinner settings on the machine. Cut each strip into 12-inch (30 cm) lengths; hang over rack to dry slightly. Cut into fettuccine shape using pasta machine, or by hand, rolling each length into loose roll, then slicing thinly to make 1/4-inch (5 mm) wide strips. Let dry on rack while preparing sauce.
While the sauce is simmering, cook fettuccine until tender but firm in a large pot of boiling salted water, about 3 minutes.
Drain, reserving 1/2 cup (125 mL) of the cooking liquid. Return pasta to pot; sprinkle with 1 cup (250 mL) of the cheese, salt and pepper and reserved pasta liquid. Toss gently; add sauce and toss again gently to coat pasta evenly.
With tongs, transfer to 6 warmed pasta bowls. Sprinkle with remaining cheese and a few strands of lemon rind.
With a zester, remove long strands of lemon rind from 1 of the lemons; set aside. Squeeze juice from both lemons to make 1/2 cup (125 mL). In a small saucepan, bring lemon juice, cream and butter to boil. Reduce heat and simmer until slightly reduced, about 5 minutes.