This is good one from Taste of Home
The club soda in this keeps it light, like beer does.
Oh, I see that your friend wanted a batter for baked fish. Not sure how that would work, I've never baked anything that has been coated, but this is good for fried fish, anyway.
2 tablespoons all-purpose flour
2 to 3 tablespoons cornstarch
1/4 teaspoon each garlic powder, onion powder, salt, cayenne pepper and paprika
1/8 teaspoon dried oregano
1/8 teaspoon dried thyme
1/3 cup club soda
Coat fish with flour; in a shallow bowl, combine the cornstarch, seasonings, and soda.
In a heavy skillet, heat 1 inch of oil. Dip floured fillets into batter and fry over medium heat for 2-3 minutes on each side or until the fish flakes easily with a fork.