Chop the parsnips into 1-inch pieces. Cut the potatoes into pieces slightly smaller. Place parsnips, potatoes, garlic, and water to cover, in a large pot. Add some salt and white pepper. Cover and bring to a boil, reduce heat and simmer until soft, about 20 minutes.
Chop the carrots into 1-inch pieces. Cut the potatoes into 2-inch pieces. Place the carrots, potatoes, ginger and water in a pot. Add some salt and white pepper. Bring to a boil, reduce heat and simmer until soft, about 30 minutes.
For each batch: Drain water from cooked vegetables and puree, doing white-colored vegetables first, through a food mill adding the butter, the heavy cream, salt, and white pepper to both batches. Add 2 tablespoons maple syrup to the carrot puree. Stir each batch in its own bowl until all ingredients are incorporated. Wrap 1-cup of each batch in plastic wrap to form a "bullet" shape, continuing until all the batches are used. You can make these ahead and microwave them just before dinner. Scoop a hot bullet into a pastry bag and pipe into a casserole dish, repeating with rest of bullets.
Note: A viewer, who may not be a professional cook, provided this recipe. The FN chefs have not tested this recipe and therefore, we cannot make representation as to the results.