Ingreadient :

For the sofrito:

• 1 ½ pounds ripe medium-size ripe red tomatoes (any variety)
• 2 tablespoons grapeseed oil or other neutral-flavored oil, or more if needed
• 2 tablespoons olive oil, or more if needed
• 2 cups finely chopped yellow onions
• 2 tablespoons finely chopped garlic

For the fish: 

• 1 tablespoon grapeseed or other neutral-flavored oil
• 1 tablespoon olive oil
• 2 skin-on white fish fillets (6 ounces each) such as sea bass, tilefish, or cod
• Kosher salt
• 1 cup white wine
• 1 cup fish stock

Direction :

Make the sofrito:

1. Cut tomatoes in half crosswise. Place a box grater in a large bowl. Grate tomatoes, cut side against the coarse side of the grater, until only the skin remains; discard the skin. You should have about 2 1/2 cups of grated tomatoes with juices. Set aside.
2. In a large skillet, heat grapeseed and olive oils over medium heat. Add onions and cook, stirring often, until deep golden brown, adding more oil if the onions are sticking, about 15 minutes. Mix garlic into onions.
3. Add grated tomato and cook, stirring occasionally at first, then often during the last 15 minutes or so, until liquid has evaporated, mixture is reduced by 3/4 and is deeply red and caramelized, and you begin to see a separation of oil from the vegetables, 30 to 40 minutes. Add a splash of water to skillet to loosen any bits from the bottom of the pan and stir until evaporated. Let cool.
4. Set 1/4 cup sofrito aside for the fish. Divide remaining 3/4 cup sofrito into smaller portions in freezer-safe containers or an ice-cube tray. Refrigerate or freeze for later use.

Make the fish:

1. Heat both oils in a large skillet over medium-high heat. Season fish with salt. Add fish to skillet skin-side down. Cook until skin is crisp and lightly browned, using a spatula to occasionally press fish to help skin brown evenly, 2 to 3 minutes. Turn fish over and cook for 1 or 2 minutes, then transfer fish to a plate (it will not be fully cooked).
2. Add 1/4 cup sofrito to skillet and stir until heated through, about 30 seconds. Add white wine and fish stock and cook until sauce has reduced by half and is thick enough to coat the back of a spoon, 3 to 5 minutes. Reduce heat to medium, add fish skin-side up, and simmer until fish is cooked through, 2 to 3 minutes. Divide fish and sauce among shallow bowls and drizzle with good extra-virgin olive oil and top with a sprinkle of flaky sea salt.