I made a new recipe -that had chicken, mushrooms and onion sauteed in butter, to make a casserole. I made a white sauce - butter/flour, lactose-free milk, and it thickened very slowly, so added some cornstarch, and it thickened nicely.
As the recipe said, I whisked in one cup of heavy cream, poured it over the chicken/mushroom/onion garlic mixture, then put it in a 13x9 glass tempered dish, covered with foil, tightly, and put it in an oven at 150°C (300°F); and it was in there for two hours, maybe 2.5.
When I got it out, it was brown, through and through, and it looked like butter had separated; no white cream sauce to be seen. The flavors were separate, and althoguh I didn't like it, my husband ate it, and I am thinking it was burned through and through -- but I am not sure this was the way it was supposed to turn out.
The original instructions didn't have 2.5 hours at 150°C (300°F), but 100°C (225°F), for 2-3 hours - and the recipe used a dutch oven, which I don't have. The higher heat was an oversight.
Did I burn it? Is it just overcooked, and edible, or is it bad? I have absolutely no idea at this point, but I have been reading that cream sauces have a top heating level of 200, so I think I really blew it with the 300 degrees.