Tagliatelle with asparagus in a parmesian and creme fraiche sauce

This is a tangy and fresh version of carbonara - the creme fraiche adds a depth of flavor to the dish.  Adapted from The River Cafe Cook Book Green

Ingredients

500g-1kg asparagus, ends trimmed
500g tagliatelle (fresh is ideal)
250g parmesian, grated
1 garlic clove, peeled and crushed
400ml creme fraiche
2 large eggs
salt and pepper to taste

Instructions

1. Fill a medium pot halfway with water, and bring to a very gentle simmer
2. Rub the crushed garlic around the surface of a small-medium saucepan, and add creme fraiche, parmesian, and egg yolks
3. Heat small pan filled with creme fraiche on top of medium pot filled with water - stir gently and cook until sauce thickens, about 15-20 minutes (or until sauce reaches around 65C)
4. Bring a large pan of water to boil, and season with 2 tablespoons of salt
5. Prepare asparagus by slicing stems and tips into 1" pieces on the diagonal
6. Cook pasta - read cooking instructions on pasta package, and add asparagus to boiling water so that it cooks with the pasta for the final 3-4 minutes, until both are al dente
7. Drain pasta and asparagus, pour creme-fraiche sauce over and toss to mix