Heat oil in a large non-stick frying pan over medium heat. Add sausages and cook, turning occasionally, for 2 to 3 minutes or until evenly browned. Remove to a plate lined with paper towel.
Add onion, garlic and eggplant to pan. Cook, stirring often, for 5 minutes or until eggplant is golden. Stir in chilli and tomatoes. Cook for 5 minutes or until sauce thickens.
Add stock and bring to the boil. Spoon eggplant mixture into slow cooker. Add sausages. Cover and cook on HIGH for 4 hours or LOW for 6 hours.
Stir in parsley. Season with pepper. Serve with steamed vegetables and crusty bread, if desired.