Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper or lightly grease it with cooking spray.
In a small bowl, whisk together the Dijon mustard, olive oil, honey, garlic powder, thyme, rosemary, salt, and pepper until well combined.
Place the salmon fillets skin-side down on the prepared baking sheet. Brush the Dijon mixture generously over the top of each fillet.
Arrange lemon slices on top of the salmon for added flavor.
Bake in the preheated oven for 12-15 minutes, or until the salmon flakes easily with a fork and is cooked through.
Remove from the oven and let it rest for a few minutes. Garnish with fresh parsley if desired before serving.