As for the cleaning of the fish, the fishmonger has often taken care of this in advance - and otherwise you can always ask him to do it. It eases some of the work for you.

Split the cleaned fish lengthwise by cutting from the tail and upwards - stop just before the head.

Rinse the lemon and cut it into thin slices.

Distribute the lemon slices inside each trout.

Rinse the thyme sprigs and distribute them likewise inside each trout.

Wrap each fish in its own foil package.

My immediate thought was that the fish would probably need about 15 minutes on the grill over indirect heat. However, I got a super good tip that ensures both that the fish is done and that it doesn't get overcooked: The skin should be easy to pull off, and the meat should just separate from the bones.

I checked the fish after 15 minutes, and they were not ready yet. After another 3 minutes, they were perfect. Our trout weighed 350 grams and 450 grams respectively, and they come much larger than this, so the cooking time will naturally vary. If you use the tip of pulling the skin off and checking if the meat separates, you're pretty well covered.

Unwrap the finished fish at the table and remove the skin, so everyone can enjoy the delights :-)

We subsequently sprinkled a little salt over each of our servings.

Serve with your favorite side dish - for example, try these salt-baked potatoes, which are, among other things, absolutely perfect for grill parties.