Heat some oil in a pan, then add the onion and fry until fragrant. Add in the garlic and continue to cook, stirring often, for a few minutes.
Add in one apple and the squash and continue to cook, stirring frequently, for five minutes.
Add in the veg stock, then bring to a simmer and cook until the squash has softened. Blend smooth, seasoning to taste, adding more liquid if desired.
Now, gently fry the remaining apples until caramelised. Sprinkle with a touch of sugar, if desired. Heat the sage until crisp. Serve scattered on top of the soup.