Chop the onion into chunks. Peel and core apples, Then cut into eighths. Brown the bratwurst for 10 minutes or so. Cut into 1/2 big pieces. Chop or shred the cabbage. In a large pan, cook the onions in the oil and butter over medium heat until browned, about 7 to 8 minutes. Add 2 C. of the stock and cook until nearly all the liquid has evaporated, about 15 minutes or so. Add the apples and cook, stirring gently, for 1 minute. Add remaining 6 C. stock along with the bratwurst, cabbage and caraway seeds.Cook until the sausage is heated through and apples are tender, 7 to 8 minutes. Season with salt and pepper and serve immediately.