From: Rachel Allen: Easy Meals
One of my guilty pleasures is a tin of boiled condensed milk (dulce du leche). If you want to make your own, boil unopened tins of condensed milk for 2 hours. I like to prepare a few at a time and then keep them in the cupboard where they will store for months!
Allow to cool slightly before serving.
If you are cooking this dish for quite a few people, you can lay the fish on an oiled oven tray, drizzle a little oil over the top of each fish, and cook under a hot grill for 3–5 minutes on each side or until the skin is crispy and the fish opaque all the way through.