Step 1

Preheat oven to 450F. Coat a baking sheet with cooking spray.

Step 2

Rub cod with 2 teaspoons oil. Sprinkle with pepper. Place on the prepared baking sheet. Transfer to the oven and roast until the fish flakes easily with a fork, 15 to 20 minutes, depending on the thickness of the fillet.

Step 3

Meanwhile, heat the remaining 1 teaspoon oil in a small skillet over medium heat. Add shallot and cook, stirring, until beginning to soften, about 20 seconds. Add tomatoes and cook, stirring, until softened, about 112 minutes. Add olives and capers; cook, stirring, for 30 seconds more. Stir in oregano and vinegar; remove from heat. Spoon the tapenade over the cod to serve.