Preheat your oven to 400°F (200°C). Line a baking sheet with foil or parchment paper for easy cleanup.
Prepare the salmon: Place the salmon fillet skin-side down on the prepared sheet. Pat it dry with paper towels, this helps the seasonings stick and ensures crisp edges.
Make the butter-garlic mixture: In a small bowl, whisk together olive oil, melted butter, garlic, lemon juice, zest, salt, pepper, and dill.
Brush or pour the mixture evenly over the salmon. Use the back of a spoon to spread it, making sure every inch is coated.
Top with lemon slices and a sprinkle of parsley.
Bake uncovered for 12–15 minutes, depending on the thickness of your fillet. The salmon is done when it flakes easily with a fork and reaches 135°F–140°F internally.
Optional finish: For crispier edges, broil for 1–2 minutes at the end, just keep an eye on it so it doesn’t overcook.
Rest and serve: Let the salmon rest for 3–5 minutes before serving. Garnish with fresh herbs or an extra squeeze of lemon.