Preheat oven or grill to 375°
Mix the chopped basil into the softened butter and set aside
Lay out foil for holding individual Salmon fillets. Foil should be about 12-15 inches in length
Spray foil with non-stick cooking spray
Place salmon in the center of the foil, skin side down
Put a spoonful of the basil butter mixture on top of salmon and press down slightly with a spoon along the top of the salmon and sprinkle with salt and pepper
Place 1 lemon slice on top of each salmon fillet
Add 4 asparagus stems to each packet (rub butter mixture on top of asparagus for extra flavor)
Sprinkle 2-3 tablespoons of the tomatoes on top of lemon layer
Sprinkle with salt to taste and grind fresh pepper over the top
Pull top and bottom of foil up and roll down until it seals in the center. Fold over the sides several time toward the center to seal and form the foil packet.
Place foil packets on a baking sheet or directly on grill and bake for 20 minutes.
Open steaming packets carefully and transfer to plates.