First, cut open all cloves and place garlic bulb in the middle of the foil. Drizzle with olive oil.
Next, wrap the garlic in the foil, and roast at 400 degrees until soft and golden.
Next, boil the parsnips, potato, and a teaspoon of salt in a pot until the parsnips are fork tender.
Next, add all other ingredients except the cheese, and use an immersion blender to blend everything to a mashed texture.
Finally, add in the Parmesan cheese and salt and pepper to taste.
Garnish with fresh thyme leaves if desired, and dig in!