01 - Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper or lightly coat with nonstick spray.
02 - In a small bowl, whisk together Dijon mustard, olive oil, lemon juice, lemon zest, minced garlic, honey, thyme, salt, and black pepper until thoroughly blended.
03 - Place salmon fillets on the prepared baking sheet, skin side down if present. Pat each fillet dry using paper towels.
04 - Brush the lemon Dijon marinade liberally over each salmon fillet, covering all exposed surfaces for maximum flavor.
05 - Top each salmon fillet with a thin lemon slice to infuse additional citrus aroma during cooking.
06 - Transfer the tray to the oven and bake for 15–18 minutes, until the salmon is opaque throughout, flakes easily with a fork, and reaches an internal temperature of 145°F (63°C).
07 - Optionally, sprinkle with chopped fresh parsley. Serve immediately for best texture and flavor.