Heat olive oil in a large pot over medium heat.

Saute the onion for 10-15 minutes, until soft and almost browned.

Add the diced fennel and apples to the pot.

Cook for 5-10 minutes until the fennel and apples start to soften or brown.

Pour in the chicken stock and add the thyme sprigs.

Bring the soup to a simmer and cook for 15 minutes to allow the flavors to meld.

Remove the thyme sprigs from the soup.

Carefully puree the soup in small batches in a blender until smooth and creamy.

Return the pureed soup to the pot.

Reheat the soup gently before serving.