Break off ends of asparagus.
For the butter:
Mix rub into butter. Spread the butter mixture lengthwise across a piece of plastic wrap. Roll the butter up tightly into a log and twist the ends. Refrigerate.
Preheat grill. If using a stovetop grill, use medium-high heat. Gently toss asparagus with seasoning, oil and salt and pepper, to taste. Grill asparagus until tender, turning once, about 6 minutes. Serve with barbecue butter.
Mix ingredients together and store in an airtight container for up to 6 months.