- Stir together the cornstarch and sugar, and place in a saucepan.
- Stir in the evaporated milk, and chocolate chips.
- Cook over medium heat until chocolate is melted and the mixture is thickened.
- Stir constantly to prevent burning.
- Remove the mixture from the heat, and stir in the plain yogurt and vanilla. Refrigerate until chilled.
- Pour the mixture into an ice cream maker, and freeze.
- This will be ready in 2 hours.