1) The left over poaching oil can be used again for more poaching, or in salad dressing, with pasta, for croutons, etc. After removing the cooked fish from the baking dish, allow the oil to thoroughly cool, then remove lemons, garlic or herbs. Top a glass or other round container with a paper coffee filter. Pour the oil into the coffee filter, a little at a time. The oil will slowly drip from the filter and the cooking bits will be removed. Discard the filter when finished. Cover oil tightly and refrigerate until next use. The oil will keep for about 2 weeks.
2) This is also a great dish when planning ahead for a dinner party. Cook the fish as directed, allow it to cool, then place the whole dish in the refrigerator for up to a few days. When ready to serve, simply re-heat in a low oven.