Step 1

Stir together milk and sugar in a heavy bottomed saucepan.

Step 2

Bring to a boil, then reduce heat and simmer uncovered, stirring occasionally, until caramelized and thickened, about 1 1/2 to 1 3/4 hours. (skim away any foam that forms during simmering)

Step 3

After about an hour, stir more often as milk caramelizes, to avoid burning.

Step 4

Remove from the heat and stir in vanilla extract.

Step 5

Transfer to a bowl to cool. Makes about 1 1/2 cups.