Heat the chicken stock and sage in a large Dutch oven or stock pot. Bring to a simmer and then simmer very gently while you prep your garlic.

Remove the skins from the garlic cloves and slice them in half lengthwise. Remove the little embryonic shoot.

Bring a small saucepan of water to a boil and add the garlic cloves. Boil for 3-4 minutes. Drain the cloves.

Use the back of a fork to mash the softened garlic. Add the mashed garlic to the stock and continue to gently simmer for 10 minutes.

Put the egg yolk, mustard, salt and oil in a small jar. Blend with an immersion blender.

If your mayonnaise does not instantly become thick and creamy, add the egg white and blend again.

Strain your soup for a velvety smooth texture, if desired. Return strained soup to the pot.

Take a ladle-ful of the hot soup and stir it into your mayonnaise to temper it. Then stir the mayonnaise into the soup pot.

Bring the soup back to temperature, but do not let it boil.

Serve with crusty croutons, an extra drizzle of olive oil, a sprinkle of smoked paprika, and fresh parsley if you like.