Pour the oil out of the skillet and wipe it clean. Return it to high heat, add the butter, the remaining olive oil, cherry tomatoes, and parsley, reserving a little of the parsley for
garnish. Cook for 30 seconds, stir in the strained tomatoes, cornichons, capers (if using), Worcestershire sauce, and lemon juice. Season with salt and pepper, bring to a simmer, add the haddock, and heat through.