Set aside about 2/5 cup (100 ml) of the milk. Put the rest of it to heat up on the stove, then add the sugar and stir until it dissolves.
In a separate container, pour the set aside cold milk, eggs and flour and beat until homogeneous.
Next, pour the mixture into the hot milk while stirring to prevent lumps. Let it boil for 5 min. after boiling point.