Fill a large stock pot with water and a generous pinch of salt. Add the cauliflower and bay leaves, and bring to a boil, then reduce to a simmer.
Cook the cauliflower until slightly tender, then add the potatoes in with the cauliflower, and cook until the potatoes are tender to the probe of a fork.
Drain the cauliflower and potatoes in a colander, shaking off the excess water.
Pass the cauliflower potato mixture through a ricer or food mill, squeezing the mixture back into the hot stock pot to help steam away any excess moisture.
Discard the bay leaves.
Add the chicken stock and olive oil, then season with salt and pepper, tasting to adjust the seasoning.