I made a pear and cauliflower soup with no milk/cream/potatoes. It separated slightly in the fridge, how can I save it?

By the way, I think the hazelnuts in the original recipe helped emulsify the soup and keep it together.
If you have some and no reason not to use them, try adding them.
Other possible emulsifyers, to hold the soup together - small amounts of egg yolk, mayo, prepared mustard

I'd try giving it a whiz with an immersion blender!