Shrimp and Asparagus Foil Packs with Garlic Lemon Butter Sauce

Contents:
1 1/2 lbs large (21/25) shrimp, peeled and reserved
2 tablespoons dry white wine or chicken broth
4 teaspoons minced garlic (4 cloves)
2 teaspoons lemon zest
Salt and freshly ground black pepper
6 tablespoons butter, chopped into small cubes
1 1/2 tablespoons fresh lemon juice
2 tablespoons chopped fresh parsley
1 lb medium asparagus, woody ends trimmed