Here is 2 ways I like to cook my trout.
1st way, Depending on how many fish I am cooking the amount of ingridents will vary. I use regular flour with some garlic salt, lemon pepper, fresh ground pepper, and a little sea salt all mixed together. I then take my trout whole or boneless and roll them in the flour mixture and then fry them in oil until golden brown. For the oil I like either vegetable or a good extra virgin olive oil. I usually do not put anything on them except maybe a little lemon juice somtimes.
2nd way. I like to take the trout whole and wrap them in foil that has been buttered (to help from sticking). For seasonig, I like to use fresh chopped onion, fresh chopped celery or celery salt, lemon or lime slices and more butter. I then take the wrapped fish and put it on the grill. The fish is done when it flakes eith a fork.
I hope this helps and I even make trout jerky but that is another story.
Tony