Leche flan is either steamed or baked. There are innumerable ways to make this popular dessert in an oval (or any shape) mold called a llanera/lyanera (lya-ner-AH) that has been lined with caramelized sugar.
1 cup white sugar
1/8 cup water
1/8 white vinegar
8 egg yolks
¾ cup sugar
1½ cups fresh milk
1. Preheat oven to 350°F. Fill a 13x9 roasting pan halfway with water. Let heat inside the oven while it preheats. This is the water bath.
2. Meanwhile, mix ingredients for caramel in a heavy-bottomed sauce pan. On medium heat, stir until sugar has dissolved. Once mixture boils, do not stir. Let mixture boil until it becomes a light golden brown. Immediately drizzle the caramel into a 9x5 loaf pan or into 2 llaneras. Tilt the pan(s) so that the caramel completely covers the bottom(s).
3. In a bowl, thoroughly mix the flan ingredients. Strain mixture into the prepared pan(s). Place mixture into pan(s). Cook in the water bath for 40 minutes, or until 1 hour. A knife inserted in the middle of the flan should come out clean.
4. Cool the flan still in the water bath at room temperature for 30 minutes. Remove from the water bath and un-mold onto a platter.