Cooking the salmon at a low heat makes for tender meat and a vibrant hue. Set off the fish's decadence with a little basil and a burst of tangy-sweet tomatoes.
Preheat oven to 350 degrees. In a 9-by-13-inch baking dish, toss together oil, tomatoes, garlic, and 4 basil leaves. Season with salt. Bake until tomatoes are just wilted, about 20 minutes. Remove from oven and reduce heat to 275 degrees.
Season salmon with salt and pepper; place, skin-side down, in dish with tomatoes. Spoon pan juices over fish and bake until just cooked through and a thermometer inserted into thickest part registers 120 degrees, about 15 minutes. Serve, sprinkled with remaining basil leaves.