Preheat oven to 400 degrees. Peel, halve, and finely chop the shallot. Finely chop the walnuts. Strip the thyme leaves off the sprig and roughly chop the leaves.
Toss the broccoli on one side of a lightly oiled baking sheet with a drizzle of olive oil and a pinch of salt and pepper. Place in the oven for 15-20 minutes, until golden brown and slightly crispy.
Heat 1 tablespoon butter in a small pot over medium heat. Add the shallot and cook, tossing, for 4-5 minutes, until softened. Add and 1½ cups water and the stock concentrate and bring to a boil. Once boiling, add the couscous, cover, and set aside off the heat.
In a small bowl, combine the panko, chopped walnuts, thyme, and 1 teaspoon oil. Season with salt and pepper. In another bowl, combine honey and Dijon mustard to make the glaze.
Remove the baking sheet from the oven. Place salmon on the opposite side of the baking sheet and season with salt and pepper. Evenly coat each fillet with the honey-dijon glaze. Press the panko mixture onto the top of each fillet and place in the oven for 10-12 minutes, until salmon is opaque in the center and the broccoli is golden golden brown.
Fluff the couscous with a fork. Serve with the broccoli and salmon on top.