Preheat the grill to medium, about 350 to 375 degrees F.
Lay 4 large squares of foil on the countertop.
Cut the butter into 4 sections.
Slice the lemon into rounds.
Place one tablespoon of butter and one lemon slice in the center of each piece of foil.
Pat each cod fillet dry with a paper towel. Then lay one fillet over the butter and lemon on each piece of foil.
In a small bowl, mix the lemon pepper seasoning, garlic powder, and smoked paprika. Sprinkle generously over the top of each fish fillet.
Pull the two opposite sides of the foil up over the cod. Fold the foil down twice to seal the top. Then flatten and fold the two ends together, twice, to make the foil packets airtight.
Place the foil packets on the hot grill. Cover the grill for 8 to 10 minutes. 8 minutes for fillets under 1 inch thick. 10 minutes for fillets over 1 inch thick.
Remove from the grill. Once the foil is cool enough to touch, open the packets and serve warm.
