Pat dry the trout before seasoning it with the salt and pepper. Rub the lemon juice all over each fillet.
Add the oil to a non-stick pan over medium heat. Place the trout fillets flesh side down onto the pan, pressing lightly so that it sears. Sear for 3-4 minutes, until crispy and golden. Flip and cook for a further two minutes. Add the butter, garlic, and a pinch of fresh parsley, and stir around each fillet.
Remove from heat, drizzle with extra butter and sprinkle with more parsley.
TO STORE: Leftovers can be stored in the refrigerator, covered, for up to three days. TO FREEZE: Place the grilled and cooled fish in an airtight container and store it in the freezer for up to two months. TO REHEAT: Microwave the fish for 30-40 seconds or reheat in a non-stick pan until crispy.