In a medium-sized mixing bowl, combine sausage, egg, crushed crackers and sage. Separate the mixture into two balls.
Heat a skillet to a high heat and brown the sausage balls. Drain on paper towels. Transfer the balls to a container with a lid.
Combine ketchup, vinegar, brown sugar and soy sauce in a small pot. Stir while heating the sauce. Let the sauce come to a boil, then reduce the heat to simmer. Let the sauce simmer for 20 minutes before pouring the sauce over the balls.
Allow to cool, then cover the balls and sauce, and refrigerate overnight. Reheat before serving.
A good recipe, however we made small 1" balls instead of the two balls the recipe called for. Works great for a party appetizer when the recipe is doubled or tripled.
I made smaller balls also, and instead of pouring the sauce over the meatballs, once they were thoroughly cooked through, I poured the sauce, mixed with about 1/2 cup water, over them and simmer...