Spring Vegetable Penne with Lemon-Cream Sauce

extra-virgin olive oil

chopped Vidalia or other sweet onion

presliced mushrooms

chopped fresh thyme

garlic clove, minced

all-purpose flour

fat-free, lower-sodium chicken broth

half-and-half

frozen green peas

shaved Parmesan cheese, divided

grated lemon rind

fresh lemon juice

salt

freshly ground black pepper

uncooked penne

(1-inch) diagonally cut asparagus