Preheat oven to 450°F. Line a baking tray with foil (or grease the baking sheet).
Rinse fish and with paper towels, pat dry inside and out.
Score the top of each fish three times on a diagonal (see images).
Using a silicone brush or pastry brush, brush both the inside and outside of the fish with oil. Arrange fish on the baking tray.
In a small bowl (or on a small piece of foil paper), mix together garlic and turmeric. Spread ¼ of the mixture on the inside of each fish. Sprinkle the inside of each fish with 1 teaspoon of Italian dressing mix (or Italian seasoning, salt, and pepper).
Add 3 slices of lemon and 1 sprig of rosemary to the inside of each fish.
Sprinkle the outside of each fish with ¼ teaspoon each of garlic powder, salt, and pepper.
Bake for 15-20 minutes, or until the internal temperature of the fish reaches 145°F.
Optional step for crispy skin: Move baking sheet to the top rack, and turn oven up to broil. Broil for 2 (or more) minutes to reach desired crispiness, and remove from the oven quickly. Watch it carefully!
Squeeze the remaining lemon over the fish and serve.
Notes
*If using optional grated fresh turmeric, take care to wear an apron and consider using gloves, as it dyes what it touches yellow. It will also turn the fish a colorful yellow inside, while giving it a pleasant earthy flavor.