The technique of roasting salmon mounted on cedar planks was used for thousands of years by Native Americans in the Pacific Northwest, where both salmon and cedar were abundantly available. The essence of the wood infuses into the salmon while keeping the fish tender. We've adapted this distinctly American technique for the home kitchen so you can enjoy moist, delicate salmon alongside delicious potatoes and green beans.
Place cedar sheets in a shallow bowl or pan. Add enough water to cover and soak 10 minutes. While sheets soak, cut potato into ¼" slices. Halve and peel onion. Cut halves into ½" slices. Set aside two thyme sprigs. Stem and coarsely chop remaining thyme. Cut twine into four equal pieces. Trim ends off green beans. Pat salmon fillets dry, and season flesh side with ½ tsp. salt and ¼ tsp. pepper.
Roast the Potatoes
Place potatoes and onions on prepared baking sheet. Toss with stemmed thyme, 1 Tbsp. olive oil, ½ tsp. salt, and ¼ tsp. pepper and spread into a single layer. Roast 13 minutes. Vegetables will finish cooking in a later step. While vegetables roast, sear salmon.
Sear the Salmon
Lay two parallel pieces of twine 3" apart on counter. Place a cedar sheet on top of twine. Place a medium non-stick pan over medium-high heat. Add 1 tsp. olive oil and salmon, skin side up, to hot pan. Sear undisturbed until lightly browned, 2-3 minutes. Transfer a salmon fillet, skin side down, to middle of cedar sheet. Place a remaining thyme sprig on salmon. Enclose cedar snugly around salmon and secure with twine. Repeat with second salmon fillet. Wipe pan clean and reserve.
Roast the Salmon
Carefully, move vegetables to one half of baking sheet (some overlap is fine) and place cedar-wrapped salmon on other half. Roast until cedar sheets are lightly browned and salmon reaches a minimum internal temperature of 145 degrees, 7-9 minutes. Remove from oven and rest 3 minutes. Cut twine and remove from cedar paper.
Cook the Green Beans
Return pan used to cook salmon to medium heat. Add ½ tsp. olive oil and green beans to hot pan. Cook, stirring often, until green beans start to brown, 1-2 minutes. Add ¼ cup water and cook until green beans are tender, 2-4 minutes. Remove from burner and season with ¼ tsp. salt and a pinch of pepper.
Plate the Dish
Place potatoes, onions, and green beans on a plate and place salmon next to potatoes.