1/4 c. vinegar
1/4 c. sugar
Dash of salt
2 tsp. cornstarch
1 tbsp. water
1 tbsp. oil
2 tbsp. tomato ketchup

Combine first 4 ingredients and set aside. Heat oil and pour in ketchup and water. Stir. Add rest of ingredients constantly, stirring until it boils and thickens.