Place the meatballs, green beans, onion, and pineapple slices in a large resealable freezer bag.
In a small bowl, mix together the brown sugar and flour. Stir in the vinegar, water, soy sauce, and ketchup.
Thaw.
Spread all of the ingredients in a single layer on a cookie sheet lined with parchment paper and bake at 400° for 20 to 30 minutes.