- Preheat oven to 400 °F.
- Bring large pot of water to a boil.
- When water boils, lightly salt water, then rutabaga, carrots and sweet potato slices and boil 5 minutes.
- Drain, reserving about ½ cup of cooking liquid.
- In dutch oven, heat oil over medium heat.
- Add onion, garlic, ginger and turmeric and cook, stirring often, 3 to 4 minutes.
- Add coriander and cumin seeds to mixture, then add drained sweet potatoes, rutabagas and carrots.
- Toss gently over heat 5 minutes.
- Pour ½ cup of reserved cooking liquid over vegetables, and squeeze lemon juice over top.
- Cover and bake 1 hour.
- Remove cover.
- Scatter sunflower seeds over top and bake 10 minutes more.
- Serve warm.