In a large skillet over medium-high heat, add the brown sugar, vinegar, ketchup, soy sauce and 2 cups of the pineapple juice. Bring to a boil.
Make a slurry by mixing the cornstarch into the remaining 1/4 cup pineapple juice, whisking to get out all the lumps. Whisk the slurry into the skillet and add the All-Purpose Meatballs. Bring to a simmer and add the sriracha. Cover and cook until the sauce is thickened and the meatballs are heated through, 8 to 10 minutes. Stir in the pineapple chunks.
Serve over steamed rice, garnished with green onions.
To make the meatballs, combine the ground beef, breadcrumbs, milk, cream, parsley, mustard, salt, black pepper, red pepper flakes and eggs in a large mixing bowl. Mix together well with your hands. Scoop out 1-tablespoon portions and roll them into balls with your hands. Place the meatballs onto parchment-lined baking sheets and put the baking sheets in the freezer for 5 to 10 minutes for the meatballs to firm up.
To brown the meatballs, heat the olive oil in a heavy pot or large skillet over medium-high heat. Add the meatballs in batches, making sure not to overcrowd the pot. Cook, turning the meatballs to make sure they brown all over, 5 to 7 minutes per batch. Drain on paper towels.
Freezer instructions: Put the cooked meatballs in a single layer on baking sheets and put into the freezer. When frozen, divide them into freezer bags, 25 per bag, and return them to the freezer. Yield: 125 meatballs.