This soup is perfect for a chilly spring day. It could be made from perennial walking onions or leeks overwintered in your garden instead of the onions. And don't forget to leave some parsnips in your garden in the fall to dig out fresh in the spring!
Melt butter in a medium pot over medium heat. Add onions and parsnip and cook until softened. Add flour and cook about 1 minute, stirring constantly. Add broth and milk and bring to a simmer. Cook until slightly thickened, about 5 minutes, stirring occasionally. Add salt and nutmeg. Add cauliflower and simmer 5-10 minutes until thawed (if frozen) or cooked through (if fresh). Blend and serve. Add more broth or milk if it gets too thick.