In a small casserole dish, add the milk and heat over medium heat until boiling. Turn off the heat and set aside.
In another casserole dish, dissolve the sugar and heat over low heat, stirring constantly, until you obtain a smooth, shiny caramel.
Gradually add the hot milk to the caramel, stirring after each addition to completely dissolve the sugar and obtain a smooth and homogeneous mixture.
Dilute the cornstarch in a little milk and add it to the casserole dish. Mix well and continue cooking until the mixture begins to boil and thickens.
Cook until the bottom of the casserole dish is visible, stirring constantly. Remove from heat, let cool and serve.
