- Combine cornstarch, salt, and sugar in a heavy 2 quart saucepan.
- Add evaporated milk, butter, corn syrup and vinegar.
- Cook and stir gently over low heat until sugar dissolves and mixture begins to boil.
- Continue to cook over medium heat to (238 degree F).
- Stir gently to prevent sticking while cooking candy.
- Remove from heat, cool to room temperature.
- Add vanilla and beat until stiff, approximately 10 minutes.
- Pour the mixture in buttered square pan.
- Cut it and can give desirable shapes and sizes.
- Can be served immediately, or chilled.