Make a slurry with:

   - 1 1/2 Tbs cornstarch

   - 2 Tbs water

Place in a small saucepan and bring to a boil:

   - 1 cup pineapple juice (not fresh)

   - 3/4 cup brown sugar

   - 1/3 cup vinegar

   - 3 Tbs ketchup

   - 2 Tbs soy sauce

Stir in the cornstarch slurry and while stirring constantly, simmer for at least another minute, until thickened.