1.Take a 1 quart microwavable casserole and place the asparagus in it. Pour in 1/2 cup water and microwave for 2 minutes on High 100%.
2. Now, rearrange the asparagus. Place the ones at the center to the edge and vice versa.
3.Turn the dish a1/3 circle and microwave on high 100% for 2 minutes. Let stand until asparagus becomes tender. This takes about 1 minute.
4.Meanwhile, take a small microwavable bowl and beat 2 teaspoons of water, mustard, vinegar, oil, pepper well with a wire whisk.
5. Now add in the mushrooms and stir. Microwave covered for 2 minutes on High100%.
6.Take 2 serving plates, arrange 6 asparagus spears on each plate and top with mushroom vinaigrette. 7.Discard the cooking liquid.