Preheat oven to 400 degrees F. Lay steelhead fillets skin-side down on a cutting board. With a sharp, narrow knife, cut a slit in the centre of salmon that's about 3 inches long. Divide and push stuffing into the slit. (See photo to see how salmon will look once stuffed). Place salmon skin-side down in a lightly-oiled (1 Tbsp. of the olive oil used here) baking dish. Drizzle with remaining olive oil and lemon juice and season with salt and pepper. Bake 15-20 minutes, or until fish is just cooked through. Place salmon on heated plates and spoon over pan juices. Serve steelhead with seasonal vegetables.