This is my re-creation of a fabulous dish of shrimp, scallops and crab that I enjoyed in Northern California almost 40 years ago. It made such an impression on me that I've tried to find someone... anyone... who served it ever since, but with no success. Now, here is my own version that I believe captures the original qualities I've tried so many years to find. A very nice factor with this recipe is you don't need fresh seafood to make it. We live 45 miles from the nearest fresh fish market, so we've learned to not depend on fresh fish for the success of our recipes. If you have access to fresh shellfish for this recipe, it will be even better, but if you need to use IQF seafood, the recipe will work perfectly well if you simply allow your shellfish to thaw gently, either in cold running water, or overnight in the refrigerator. The sauce is not heavy but still rather rich, and will actually thin some as it cooks because the shellfish will give up some of its moisture.