Heat the water and chicken stock in a large soup pot or stockpot. Add the split peas and bring them to a boil.
Add the ham hocks, half the parsley, the fresh thyme, and celery. Reduce the heat and simmer for 45 minutes with the cover partially on. Be sure to stir it every 10 or 15 minutes.
Heat the butter in a saucepan over medium-high heat and add the onion, leek, garlic, and carrots.
Sauté until the vegetables are soft and add them to the pot.
Add the spinach and simmer for 30 minutes, again partially covered.
Turn off the heat and remove the ham hocks. Using a small paring knife, remove the meat from the hocks being sure to trim off and discard any fatty pieces. Cut the meat up into pieces and return to the pot.
Taste and adjust seasoning with salt & pepper. Add the rest of the parsley and serve.