Lay a large piece of foil on a baking sheet or pan and place salmon on top of it.
Sprinkle top side of salmon with salt, pepper, garlic, and dill and rub in to evenly distribute seasoning.
Place butter cubes evenly across salmon. Top with lemon slices and fold foil over the top of the salmon.
Place pan in oven and bake for 15-25 minutes until salmon is cooked through in the thickest part but not over cooked (cook time depends on thickness of salmon).
Remove salmon from oven and serve right away.
Notes
Check for doneness by either by 1) using a meat thermometer - remove from oven when salmon reaches 130-135° degrees at thickest part 2) or with a knife - stick a knife or fork into the thickest part and check the inside. It should be pink and flakey yet slightly underdone in the very middle since it will continue cooking and that will keep it from becoming overdone.Undercooked is better than over cooked. If slightly undercooked (130-135° degrees at thickest part), just reseal the foil and let sit in pan outside of the oven for 2-5 more minutes.