In a mixing bowl, whisk together olive oil, apple cider vinegar, and crushed garlic until combined. Season with salt and pepper, then fold in capers, red onion, and parsley. Set aside.

Heat a large sauté pan over medium-high heat for about 2 minutes. Add olive oil and butter to the pan until melted and shimmering.

Pat fish fillets dry and season both sides with sea salt and pepper. Place fillets in the pan, cooking for 3-4 minutes on one side until golden brown, then flip and cook for another 3-4 minutes until flaky.

Transfer cooked fish to a plate lined with paper towels to drain excess oil. Arrange on a platter and spoon dressing generously over the top.

Let dish sit for about 15 minutes before serving to allow flavors to meld. Serve warm with crusty bread or salad.