Build the stock: Drain and rinse the ham hock. Put it in a large pan with the onion, carrot, celery, peppercorns and bouquet garni. Cover with water, bring to a simmer and skim off any scum. Simmer gently for 2.5 to 3 hours until the ham is tender and falls off the bone.
Prepare the ham: Lift the hock out and let it cool slightly. Shred the meat into pieces and discard the bone. Strain the stock through a sieve back into the pan.
Cook the peas: Drain the soaked split peas and add them to the strained ham stock. Simmer for 1.5 to 2 hours until the peas are completely soft.
Blend smooth: Blitz with a stick blender until smooth. Adjust consistency and season.
Make the croutons: Heat olive oil and butter. Toss bread pieces for 3 minutes until golden. Drain on kitchen paper.
Serve: Stir shredded ham back in, warm through. Ladle into bowls with croutons and parsley.
