In a large Dutch oven, pour in 4 cups of chicken stock and add a handful of fresh sage leaves. Bring to a gentle simmer over medium heat.

While the stock simmers, peel the garlic cloves, halve them, then boil for 3-4 minutes to soften their pungency. Drain and mash into a smooth paste.

Stir the mashed garlic into the stock mixture and let it bubble for about 10 minutes to infuse the flavor.

In a small jar, combine the egg yolk, Dijon mustard, and salt. Gradually drizzle in 1/2 cup of olive oil while blending until thickened into a creamy mayo.

For a smoother texture, strain the soup through a fine-mesh sieve to remove any sage and garlic bits.

Temper the mayonnaise by mixing a ladleful of hot soup into it, then whisk back into the pot over low heat.

Ladle the warm soup into bowls and garnish with croutons, a drizzle of olive oil, paprika, and chopped parsley.