"Healthy, delicious, thick sauce made with simple fresh ingredients reminiscent of a bruschetta topping cover a grilled mild white fish. I like to serve it with brown rice that has been mixed with butter and Parmesan cheese. If you are watching fat and calories, omit the butter and cheese."
Heat 1 tablespoon oil in a large skillet over medium-low heat. Add garlic; cook and stir until softened, 2 to 4 minutes. Add tomatoes, salt, and pepper; cook and stir over medium heat until heated through, about 5 minutes. Stir in spinach, basil, and capers. Cook until most of the liquid has evaporated and sauce is thick and chunky, 10 to 20 minutes.
Preheat grill for medium heat.
Rub remaining 1 tablespoon oil over amberjack fillets. Sprinkle salt and pepper on top. Grill fillets until opaque and flaky, 3 to 4 minutes per side.