Preheat your oven to 400 degrees F. Line a baking sheet with parchment paper.
In a small bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, half of the fresh dill, salt, and black pepper.
Place the salmon fillets skin-side down on the prepared baking sheet. Spoon the lemon dill mixture over the top of each fillet, making sure they are evenly coated.
Place a few small pieces of butter on top of each fillet and lay a lemon slice on each one.
Bake for 12 to 15 minutes until the salmon flakes easily with a fork and the internal temperature reaches 145 degrees F. The top should have a beautiful golden glaze.
Sprinkle the remaining fresh dill over the fillets and serve immediately with your favorite sides.