Quick Thon a la Provenasale

When it comes to Tuna, I like it best raw. But I saw Julia Child's Thon à la Provençale in her wonderful Mastering the Art of French Cooking and had to try it. I've sped things up a bit here by rapidly searing the fresh tuna without baking it and making a quicker version of Julia's sauce.
I've soured a bit on canned tomatoes and now typically take the time to blanch, peel, and seed whole tomatoes when they are in season. Grape tomatoes are an excellent choice during the winter, they'll taste much better than larger hothouse tomatoes (don't try to peel and seed them). As always, dry vermouth is an excellent, shelf-stable white white to have on hand for cooking (it's also prudent to have it on hand for the occasional emergency Martini).
Quick Thon à la Provençale (Tuna with Wine, Tomatoes, and Herbs)
3lbs Tuna Steaks, Very Fresh, Sashimi grade if possible
Sea Salt (Optional if Strictly Paleo)Freshly Ground Black Pepper6 Tbsp. Olive Oil1 Cup Finely Chopped Onion3lbs Tomatoes, blanched, peeled seeded and chopped2 Cloves Garlic, minced1/2 tsp. Dried Oregano1/4 tsp. Dried Thyme1Cup Dry White Wine1 Tbsp Tomato Paste3 Tbsp Chopped Flat Leaf Parsley
Warm your oven (175 deg. F or your oven's lowest setting). Season the steaks with pepper and salt (if using). In a heavy skillet, sear the tuna quickly in olive oil over high heat then transfer to a cookie sheet or Pyrex dish in the oven to keep warm. Reduce the heat under the skillet to medium, add the onion, and cook until softened but not browned. Stir in the tomatoes, garlic, and dried herbs. Reduce to a simmer and let bubble away for 5-10 minutes or until the sauce becomes rather thick. Increase the heat to high, add the wine and tomato paste and reduce until the sauce is once again quite thick. Taste the sauce and correct for seasoning. Plate the tuna steaks, spoon the sauce generously over each steak, and garnish with parsley.