In a bowl, combine the water, vinegar, sugar, salt and ketchup.
Mix well and set aside.
Prepare the cornstarch mixture.
In a small container dilute cornstarch in water.
Stir until smooth and set aside.
Saute ingredients
In a sauce pan, heat oil over medium heat.
Saute onion for 2 minutes or until translucent.
Add ginger and cook for 2 minutes.
Stir in the garlic and cook until golden.
Add red bell pepper and cook until soft.
Pour ketchup mixture and add garlic powder. Bring to a boil.
Lower the heat. Slowly pour the cornstarch mixture while stirring constantly to prevent sauce from clumping up.
Continue stirring until well blended.
Bring to a boil for 2 minutes and turn off heat.
Notes
When sweet and sour sauce cools down it will get thick. If you want a runny sauce don’t put too much cornstarch. Stir constantly while slowly pouring the cornstarch mixture so it doesn’t clump up.