Pre-heat oven to 375°.
Generously drizzle 9-inch x 13-inch baking dish with olive oil.
Layer apples, cabbage and onions in the baking dish; drizzle with olive oil.
Sprinkle with salt and pepper.
Arrange sausages on top.
Coat sausages with olive oil.
Cover baking dish with tin-foil; place in pre-heated oven and bake for 30 minutes.
Stir apple cabbage mixture.
Remove from oven; flip sausages, remove foil, retun to oven and bake 30 minutes.
In a medium bowl, mix sauce ingredients.
Remove from oven; evenly coat apples, cabbage and sausage with sauce.
Sprinkle with salt and pepper; return to oven and bake for 15 minutes (see next instruction).
For glossy sausages, remove from oven; brush with olive oil; retun to oven and bake for another 5 minutes; omit this step if non-glossy sausages are desired.
Remove from oven and serve.