Pre-heat oven to 350 degrees. Drizzle head of garlic with oil, wrap in foil or put in a covered (oven safe) container and bake for 45 minutes to 1 hour. This makes the soup taste yummy (roasted garlic!) so the time spent waiting for it to bake is worth it. I suppose you could use crushed garlic in a pinch, but it won't taste quite the same.
Peel and dice potatoes. Toss in a little oil/ghee, rosemary, salt and pepper. Put on cookie sheet and place in oven for 30 minutes until tender.
When garlic and potatoes are finished you can saute red onion (diced) in a frying pan for 10 minutes until soft. Add garlic (squeeze the head of garlic and it should all come out) and 1 cup of bone broth. Simmer for 5 minutes, then add 3-4 more cups of bone broth and simmer for 5 minutes. In a blender, blend together the broth and the potatoes. You may have to do this in batches. The end result should be a creamy, yummy soup. Perfect for fall.