Season the cod with salt and pepper to taste. Mix the gluten free breadcrumbs with the parsley, garlic infused oil, lemon zest, salt and pepper, then add lactose free butter and lemon juice. Mix thoroughly with your fingers.
Place the cod in a shallow, ovenproof dish and press the buttered gluten free crumbs firmly onto the cod to form an even crust.
Bake at 220C/425F/Gas 7 for 20-25 minutes until the crust is browned and the fish just cooked through. Serve immediately.