Pre-heat oven to 400º F and bring a large pot of water to boil.
In a skillet sauté onion with 2 tbs olive oil until translucent, 3-4 minutes. Add canned tomatoes, season with salt and pepper and simmer for five minutes.
Let cool down. Place in a blender and process with 8 leaves of basil, and 3 tbs olive oil. Set aside.
Season halibut, roast in the oven for 10 minutes or until thoroughly cooked.
Cook pasta according to package directions, drain, toss with tomato basil sauce, and halved cherry tomatoes over high heat for two minutes.
Top with remaining julienned basil and halibut before serving.
