Bring 1 1/4 cups water to boil in a medium saucepan. Add the oats, reduce the heat to low, and simmer until tender and thickened, 15-20 minutes. Remove from heat and cool. Puree in a food processor or blender with rosemary until smooth and creamy. Set Aside.
Place 4 1/2 cups cold water, the parsnips, carrots, turnips, and sweet potato (or rutabaga), and spices in a large pot and bring to a boil. Reduce heat to low, cover, and simmer until the vegetables are very soft, about 20-30 minutes.
Add cooked vegetables with liquid to the food processor with the oats (you may need to transfer the vegetables and blend in a few separate rounds because of the quantity of vegetables). Puree the soup until smooth, adding any extra spices to taste.
Serve topped with roasted seeds and with some yummy toasted bread!