Fettuccine with Prosciutto and Asparagus

3 c (1-inch) diagonally-cut asparagus
1 (9oz) package fresh fettuccine
1 T EVOO
1 c chopped onion
2 t minced garlic
1/2 c chopped prosciutto (2 oz)
2 t balsamic vinegar
1/2 t salt
1/8 t crushed red pepper flakes
1/8 t black pepper
1/4 c (1oz) shredded Parmesan

Cook asparagus and pasta in boiling water for 3 minutes or until pasta is done. Drain, reserving 1/2 c cooking liquid.

In dry pan, heat oil over medium heat. Add onion and garlic, cook 2 minutes, stirring often. Add prosciutto, cook 2 minutes. Stir in asparagus and pasta, cooking liquid, vinegar, salt and pepper. Toss. Sprinkle with Parmesan cheese.