How to Make It
Bring a large pot of water and 1 tablespoon of the salt to a boil over high.
While water is coming to a boil, cook bacon in a large deep skillet over medium until crisp, turning occasionally, about 8 minutes. Transfer bacon to a plate lined with paper towels, reserving drippings in skillet. Set bacon aside.
Place skillet over medium-high. Add leeks to hot drippings, and cook until wilted and beginning to brown, about 3 minutes. Add peas and garlic, and cook, stirring often, until garlic just begins to brown. Transfer mixture to a medium bowl with a slotted spoon. Reduce heat to medium; add cream to skillet, and bring to a simmer. Cook, stirring often, until slightly reduced, about 5 minutes. Add pepper, nutmeg, and remaining 1 teaspoon salt; stir to combine.
Add pasta to boiling salted water, and cook according to package directions; drain well, reserving 1 cup cooking water.
Finely chop bacon. Toss fettuccine with leek-and-cream sauce mixture over low until heated through. Add reserved 1 cup cooking water, 2 tablespoons at a time, to reach desired consistency. Divide mixture among 4 bowls; top evenly with bacon and Parmesan.