Heat olive oil and butter in a large saucepan on medium-high heat. Add onions and garlic cloves and sauté gently until soft. Add all-purpose flour and turmeric powder and stir well. Add water or vegetable stock, celery, daikon radish, potatoes, salt, and black pepper, and bring to a boil. Reduce heat and simmer for 20-30 minutes, until the vegetables are well cooked.
Use an immersion blender to puree four-fifths of the soup, leaving some vegetables whole for texture. Add optional heavy whipping cream and adjust salt and pepper to your taste.
If you feel it needs more punch, consider a squeeze of fresh lemon or a splash of white wine vinegar.Top with minced parsley for color.
MAKE THIS VEGAN
Replace butter with olive oil, and leave out the heavy whipping cream.