Make sure your trout is as clean and fresh as you can get. Wash your fish thoroughly and dry with paper towels inside and out. Keep the head on for the best presentation.

On a clean surface, open the trout and coat the inside with the spruce and zest. Drizzle the maple syrup and rum evenly.

Generously salt the interior of the fish, thoroughly covering the flesh. You should use about a ¼ cup of the salt, but don’t be afraid to use more if you need it. When it’s evenly layered, pat the salt on to keep it in place and close the fish. Salt both sides of the exterior as well.

Place the fish in a closed container and let it sit in the fridge for an hour, or a little more if your fish is especially meaty. The flesh should be noticeably firmer to your finger.

Thoroughly rinse the salt from the inside and outside of the fish and pat it dry with paper towels. Open the fish again and lay it on a wire rack with the flesh side out. Let it dry in a cool, protected place (your fridge is fine) for 2–3 hours. You want to develop a nice tacky pellicle (the skin that comes from air-drying) for the best smoky flavor. This is especially important if your smoker runs hot and the fish won’t be in as long.

Prepare your fish for smoking. Lay the trout on its side on a wire rack. Place the thyme sprigs in the cavity and use 2 toothpicks along the belly to prop the fish open about 1 inch.

Smoke your fish at 200° to 225° over alder, oak or fruitwood. You want the fish to cook through, which could take from 90 minutes to a few hours. You should aim to bring the fish to an internal temperature of 160° for 30 minutes, which will be easier after the fish has dried some already. You can also control the level of smoke by taking the fish out of the smoker and finishing the cooking process in a 200° oven.

Serve chilled or at room temperature. Present the trout whole on a plate or presentation cutting board. Run the tip of a sharp knife through the skin along the gill line and down the spine to release the skin. Then you should be able to peel the skin back easily from the head toward the tail. Offer crème fraîche and pickled red onions. Smoked trout will keep 10–14 days in your refrigerator or 2 to 3 months in the freezer.