Season the fillets with salt and pepper. In a large pan, warm the oil and add the fish fillets. Over a low heat seal the fillets on both sides, without colouring the flesh. Add chilli, garlic and the lemon zest, fry gently for 1-2 minutes developing the flavours. Combine the milk and wine, add it to the pan. Increase the heat. one the mixture has begun the boil reduce the temperature to a gentle simmer, cover with a lid (leaving a small gap).
Poach the fish fillets for 5-8 minutes until just cooked, and remove from the heat. At this stage, the sauce may appear to be slightly curdled. Remove the fillets from the cooking liquor, remove the skin and put aside. Add the mascarpone into the pan and gently stir into the sauce until well combined. Add seasoning and basil at the last minute. Serve the fish with a generous helping of Strathroy creamy mash and plenty of sauce.