Heat 1 tablespoon of water in a large pot or Dutch oven over medium heat. Add the onion, garlic and celery, and cook for 5 minutes or until soft. (Don't add salt yet-see notes.)
Add the turnips, lentils and celery seed (if using), and mix well until everything is coated and hot.
Add the prepared bouillon (or stock) and coconut milk (or plant milk), and heat until it almost begins to boil. Then reduce the heat, cover and simmer until the turnips and lentils are tender, 15-20 minutes.
Add the lemon zest and juice.
Ladle 3 cups of the soup into a blender and blend on medium speed until just creamy, being careful to allow steam to escape. Don't over blend. Add the blended soup back to the pot. Add the chopped dill, season with salt and pepper to taste, and stir.
Garnish with a few sprigs of fresh dill if desired.
If you want to avoid saturated fat, you can replace the light coconut milk with plant milk. But if you do occasionally include light coconut milk in your diet, it adds a nice flavor to this soup.
I never add salt or acid (lemon, tomatoes, etc.) to beans or lentil until they're fully cooked, as this can keep them from cooking. Red lentils are more forgiving, but some lentils will take a very long time if you forget to wait.