For the soup, peel and roughly chop the onion and parsnips. Drain and rinse the cannellini beans, then pick and roughly chop the sage.
Heat 50ml of oil in a pan over a medium heat, then cook the onion and parsnips for 10 minutes, or until softened but not coloured.
Add the bay leaf, beans, sage and stock, season and simmer for 15 minutes.
For the crispy parsnips, preheat the oven to 200ºC/gas 6.
Peel and very thinly slice the parsnip, and pick the sage leaves.
Brush the parsnip slices and sage leaves with oil, and bake for 5 to 10 minutes, checking often, or until crispy.
Remove and discard the bay leaf from the soup, then blitz it with a stick blender until smooth, adding extra stock or water if it’s too thick.
Adjust the seasoning to taste, then serve piping hot with a drizzle of olive oil and the parsnip crisps on top.
