Preheat your oven to 400°F (200°C). Drizzle olive oil on a baking tray and spread the sliced garlic. Roast for 30–40 minutes until soft and golden brown.

In a large pot, heat chicken stock over medium-high heat. Bring to boil, add salt and sage, then reduce to simmer.

Mash the roasted garlic into a smooth paste using a fork or a mortar and pestle.

Whisk egg yolk and Dijon mustard in a small bowl, gradually drizzle in olive oil while whisking to create a creamy emulsion.

Add mashed garlic and egg emulsion to the simmering stock and stir well.

Taste and adjust seasoning. Serve hot, ideally with roasted baguette slices.