1. Put the butter, mushrooms, and all but the tender tip pieces of the asparagus in a covered casserole and cook, covered, 5 minutes, stirring occasionally.
2. Add the tips and cook, covered, 3 minutes more. Chill.
3. Add all the other ingredients and toss well. Serve immediately.
NOTE:
If the tender asparagus tips were cooked as long as the rest of the spears, they would be mushy. Note the beautiful color contrast of the asparagus and the tomatoes.
