2 med. yellow squash, cut into 1/2" slices
1 med. onion, cut into 1/2" slices
Garlic salt, salt & pepper to taste
1 tbsp. butter

Alternate squash and onion slices in rows on a large sheet of aluminum foil. Sprinkle vegetables with seasonings; dot with butter.

Fold foil securely to seal; place on grill and cook over moderate heat about 40 minutes or until tender.