1. Place sheet of tinfoil on Cookie Sheet Pan large to create the bottom of a boat.
2. Lay filleted fish skin side down on foil.
3. Cut slits every 3 to 4 inches lengthwise all the way down the fillet.
4. Squish real butter in each slit. Do the same with soy sauce, plus pour generously over rest of fillet. Also add 2 tablespoons lemon juice in the slits and over the rest of the fillet.
5. Sprinkle fillet with seasonings of your choice.
6. In a bowl mix 1 cup of mayonnaise, 1 � tablespoons fresh chopped garlic, and 1�tablespoon fresh chopped basil. Mix together well and spread over fillet.
7. Place fresh onion rings on fillet.
8. Seal with tent shaped foil over fillet.
9. Bake at 357 degrees for 30 minutes or until the flesh is flaky.