Season lamb with salt and pepper.
Heat rapeseed oil in a large pot over medium heat.
Add onions and cook until soft.
Stir in the lamb and brown on all sides.
Add red lentils, lamb stock, rosemary, and thyme.
Bring to a boil, then reduce heat and simmer for 1 hour.
Add carrots, swede, and cabbage, and simmer for another 30 minutes.
Adjust seasoning if needed and serve hot.
