Preheat the oven. Set your oven to 400°F (200°C).
Line a baking sheet with parchment or lightly oil a baking dish to prevent sticking.
Prep the salmon. Pat the fillets dry with paper towels. Dry surfaces brown better and help the seasonings stick.
Make the garlic-dill mixture. Finely mince the garlic and chop the dill. In a small bowl, combine garlic, dill, melted butter, olive oil, the zest of 1 lemon, and a squeeze of lemon juice.
Stir in a pinch of salt and pepper. The mixture should be spoonable, not runny.
Season the fish. Sprinkle the salmon evenly with salt and black pepper. Place the fillets skin-side down on the prepared sheet or dish.
Add the flavor. Spoon the garlic-dill mixture over the top of each fillet, spreading it to the edges.
If you like a hint of heat, dust with paprika or red pepper flakes. Lay a thin lemon slice on each piece if you’re using them.
Bake until just done. Cook for 10–14 minutes, depending on thickness. Thinner tail pieces may take closer to 10 minutes; thicker center cuts may take 14.
The salmon is ready when it flakes easily with a fork and is opaque on the outside with a slightly translucent center.
Rest briefly. Let the salmon sit for 2–3 minutes after removing from the oven. This helps the juices settle and keeps it moist.
Finish with lemon. Squeeze a little fresh lemon juice over the top right before serving for a bright finish.
Serve. Pair with steamed asparagus, roasted broccoli, a simple salad, or herbed rice. A spoonful of the pan juices over the plate ties everything together.