To make the peperonata: In a 12 to 14 inch sauté pan, heat the 2 tablespoons of olive oil over high heat until almost smoking. Add the red and yellow peppers and sauté over high heat for 4 minutes, or until browned at the edges and softened. Add the sherry vinegar, salt and pepper. Reduce the heat to medium and continue to cook for 5 to 7 minutes, or until the peppers are tender. Adjust the seasoning and set aside to cool.


To make watercress pesto: In a blender, place watercress, extra virgin olive oil, pine nuts and garlic and blend until smooth and bright green. Season with salt and pepper and set aside.


Season perch fillets with salt and pepper. In a 14-inch non-stick sauté pan, heat 4 remaining tablespoons olive oil until smoking. Place seasoned fillets, skin side down, and gently shake pan so they do not stick. Cook 6 to 7 minutes over medium high heat until skin is crisp and fillets and cooked through. Flip fillets over, add peperonata to pan and bring to boil. Remove fish immediately to separate warm plates and divide warm pepper mixture over diagonally. Drizzle with watercress pesto and serve immediately.