Preheat the oven to 375 degrees.
Wash, peel and cut potatoes. Place on a baking sheet.
With a sharp knife, slice off the top layer of the garlic head to expose most of the cloves and peel away most of the outer layers.
Drizzle the exposed cloves and potatoes with olive oil, salt and pepper. Wrap the garlic in aluminum foil and place on the baking sheet.
Roast potatoes and garlic in the oven for 40 minutes until the garlic is fragrant.
Meanwhile prepare to make the croutons by chopping up Everything bagels into crouton sized chunks. Add the diced bagels to another sheet pan and toss with olive oil. Toss until bread is well coated and bake for 7 minutes, or until crispy and golden brown.
Working in batches (usually half of the ingredients at a time) carefully transfer ingredients to a Blendtec container and blend until smooth, adding more broth or milk as desired if a more diluted consistency is desired.
For the second batch, blend for less time or until chopped to have some chunkier consistency to the soup.
