1. Steam or boil asparagus until just barely tender to bite, 4 to 5 minutes, drain.
2. Cook pasta according to directions on package.
3. Place the cooked pasta and the tips of the asparagus in a large serving bowl.
4. Place the asparagus stems in a food processor along with the hot water, lemon juice, olive oil, garlic, and basil.
5. Whirl until smooth.
6. Pour asparagus purée over pasta, add salt, pepper, and parmesan cheese.
7. Mix well to combine.