Preheat the oven to 425°F
Line a baking sheet with parchment paper and drizzle with 1 tbsp olive oil.
In a small bowl, combine mustard, lemon zest and juice, garlic, rosemary, honey, red pepper flakes, salt and pepper.
In a shallow dish or deep plate, combine breadcrumbs, finely chopped walnuts. and 2 tsp olive oil.
Cut salmon fillet into 4 pieces. Spread the mustard mixture over the fish.
Carefully grab each piece and dip the top (flesh side) into the breadcrumb mixture, pressing lightly so it adheres. Place the fish, skin side down, onto the baking sheet.
Bake until the fish flakes easily with a fork, about 10 to 12 minutes, depending on thickness. Take out of the oven and cover loosely with aluminum foil for 5 minutes before serving.
Serve salmon with a drizzle of shallot dressing on the plate.