01 - Preheat oven to 400°F. Line a baking sheet with parchment paper or lightly grease with oil.
02 - Pat salmon fillets completely dry with paper towels. Arrange skin-side down on the prepared baking sheet.
03 - Combine Cajun seasoning, paprika, garlic powder, onion powder, thyme, oregano, and cayenne pepper in a small bowl. Stir until thoroughly blended.
04 - Drizzle olive oil evenly over each salmon fillet. Rub gently to coat. Sprinkle seasoning mixture generously over the tops. Add salt and pepper to taste.
05 - Place a lemon slice on top of each fillet. Bake for 12 to 15 minutes until salmon flakes easily with a fork and internal temperature reaches 145°F.
06 - For a crispy top, switch to broil for the final 1 to 2 minutes. Watch closely to prevent burning.
07 - Remove from oven. Sprinkle with chopped fresh parsley. Serve hot with rice, roasted vegetables, or salad.