Preheat the oven or grill to 375 degrees.
Layout large pieces of foil on the counter, one for each piece you are cooking.
Divide the vegetables between all the foil sheets and place them in the center of the foil.
Cut the salmon into however many pieces you plan on making and place them on top of the vegetables on the foil.
Pull the sides of the foil up so that the ingredients are contained.
Melt the butter with the garlic and pour over the salmon pieces.
Sprinkle with seasonings and then lay the lemon slice on top of each piece.
Pull the foil together at the top and roll it tightly closed so that the steam is contained in the packet.
Place either in the oven on a baking sheet, or on the grill over indirect heat.
Cook 20-25 minutes for smaller pieces, up to 30 minutes if cooking in 2 large pieces.
Internal temp should be 120 degrees for med-rare, 130 degrees for med-well and can go up to 145 degrees.
Be sure to pull out at 5 degrees under since it will continue to cook while it rests.