01 -
Begin by bringing the chicken stock to a gentle simmer in a large Dutch oven or stock pot. Add the fresh sage and let it infuse while you prepare the garlic.
02 -
Peel all the garlic cloves and slice them lengthwise. Here's a crucial step for the best flavor: locate the small embryonic shoot in the center of each clove and carefully remove it using a sharp knife tip or toothpick - this prevents any bitter notes in your soup.
03 -
Bring a small pot of water to a boil and cook the prepared garlic cloves for 3-4 minutes until softened. Drain well.
04 -
Take your time to thoroughly mash the softened garlic cloves with the back of a fork until you achieve a fine paste. Add this to your simmering stock and let it continue cooking gently for 10 minutes to meld the flavors.
05 -
In a jar that fits your immersion blender, combine the egg yolk, Dijon mustard, salt, and oil. Blend from the bottom up until everything emulsifies into a creamy mayonnaise. If it doesn't thicken immediately, add the reserved egg white and blend again.
06 -
For an extra silky texture, strain the soup (optional but recommended), then return it to the pot. Temper the mayonnaise by stirring in a ladle of hot soup, then whisk this mixture back into the main pot.
07 -
Gently reheat the soup until it's hot throughout, but be careful not to let it boil as this could cause the soup to separate.