Preheat the oven to 400 degrees. Coat the bottom of a baking dish with a little bit of melted butter. Place the salmon on the baking dish, skin side down. Season the salmon on both sides with salt and black pepper. In a small bowl, melt the butter and stir in the garlic, lemon zest, lemon juice and fresh dill. Pour the lemon herb butter over the salmon. Arrange the lemon slices on top of the fish. Bake uncovered for 12 to 15 minutes until the salmon flakes easily. Remove from the oven and serve garnished with extra dill.