Healthier Creamy Potato Leek Soup

extra virgin olive oil

butter

bone broth (or chicken stock)

russet potatoes (peeled and cut into large pieces)

leeks (thoroughly washed and sliced, whites only)

shallot (thinly sliced)

stalks celery (roughly chopped)

bay leaf

dried thyme

dry vermouth or white wine

Salt and freshly ground pepper

saffron (optional)

cayenne (optional)

fat-free greek yogurt