I love some store-bought sweet & sour sauces. But here's a quick and easy 'from scratch' recipe:
1 Tbls corn starch, cold water
(or use the pineapple juice)
1 8oz can pineapple chunks/tid-bits
1/4 C apple cider vinegar
1/4 C brown sugar
2 cloves garlic, crushed
1/2 tsp ginger
1 Tbls soy sauce
cooked, cubed chicken, beef or pork, or
meatballs (recipe posted recently)
Dissolve corn starch in a few tablespoons of cold water. Combine cornstarch, pineapple - including the juice, vinegar, sugar, garlic and soy in a skillet. Bring to boiling over medium-high heat, stirring regularly, until sauce thickens. Add cooked meat (or omit it for a vegetarian dish) and diced peppers, chopped onion, sliced carrots and mushrooms (or whatever other vegetables you like). How much? More of what you like, less of what you don't! :) Cook it all long enough to heat the meat through, and until vegetables are crisp-tender.
Serve with rice. And crunchy chow mein noodles. :)
It's not exactly traditional, but I love to cook this up using ground breakfast sausage for the meat. Adds a whole different flavor to the sweet & sour.