This is very tasty. I used all 2% milk and thickened it with 2 Tb of cornstarch, which leaves no floury taste and turns out smooth. I also sauteed the onions first in a tiny bit of butter with some gold bell pepper and garlic, and added a splash of white wine. We enjoyed this with some dinner rolls and a small salad of tomatoes, crispy lettuce,and blue cheese.
Excellent! I added some corn, limas, and peas. And I used cod instead of grouper.