In a large skillet, heat the butter and saute the onions, carrots, and celery for 5 minutes. Add the water, wine, and salt and pepper to the skillet. Let the mixture simmer for 5 additional minutes.
Wrap the salmon in cheesecloth and place it in the boiling liquid. Lower the heat, cover, and simmer gently for about 15 minutes (5 minutes per pound in case you bought a larger salmon steak).
Remove salmon from the skillet carefully, unwrap and serve hot.
