1.Pour evaporated milk into a small saucepan, add brown sugar, caster sugar and butter and stir over a low heat, without boiling, until the sugar has dissolved.
2.Blend cornflour with water until smooth, add to pan, stir over heat until sauce boils and thickens slightly.
3.Remove sauce from heat and stir in vanilla essence. Serve warm sauce over fruit, pancakes, waffles, ice-cream, etc.
Sauce will keep for up to 2 weeks in a covered container in the refrigerator.Note