Heat oven to 350 degrees. Place ham on rack in a shallow baking pan. Cover pan tightly with foil. Roast until an instant-read thermometer inserted in the thickest portion (not touching bone) registers 135 degrees (about 15 minutes per pound).
Meanwhile, remove and discard woody stems from asparagus spears. Arrange asparagus in a 15-by-10-inch baking pan. Drizzle with cooking oil. Sprinkle with lemon pepper seasoning.
When ham reaches 135 degrees, add asparagus to oven. Roast about 30 minutes more or until asparagus is tender and ham registers 140 degrees.
For lemon sauce, in a 1-1/2-quart saucepan, combine cornstarch, sugar, bouillon granules and pepper. Stir in water, lemon juice and lemon peel. Bring to boil; reduce heat. Cook and stir until mixture is bubbly. Cook for 2 minutes more. Stir in butter and snipped thyme or parsley.