Dulce de Leche can be made in several ways – in the oven, such as this recipe, or made in a crockpot, which makes a thicker version, as opposed to cooking it on the stovetop, which makes more of a syrup, or a more pourable version.
FROSTING, ICING, ETC RECIPE HELP

I use the thick version in the Banoffee or Banoffi Pie Recipe!

 
INGREDIENTS
2 cups canned sweetened condensed milk (21 oz)
SARAH SAYS: You can substitute with Dulce de Leche, sold in gourmet or Mexican food stores. Online or in Dean and Deluca.

INSTRUCTIONS
1. Put oven rack in middle position and preheat oven to 425 degrees F.

2. Pour condensed milk into pie plate and stir in a generous pinch of salt.

3. Cover pie plate with foil and crimp foil tightly around rim.

4. Put in a roasting pan, then add enough boiling-hot water to reach halfway up side of pie plate, making sure that foil is above water.

5. Bake, refilling pan to halfway with water about every 40 minutes, until milk is thick and a deep golden caramel color, about 2 to 2 1/2 hours. Remove pie plate from water bath.

6. Strain the caramel through a fine mesh strainer to remove any lumps. You want it to be very smooth and creamy. Be careful because the mixture is hot.

Use a heat-proof rubber spatula to push the caramel through the strainer into a bowl waiting below.

7. Then, chill the caramel, uncovered, until it is cold, about 1 to 2 hours.

STORAGE
Caramel can be chilled up to 2 days in an airtight container (cover when cooled at room temperature).