Toast the coriander seeds in a dry pan before lightly crushing in a mortar and pestle.
Put the pork pieces, wine, stock, onions, garlic and coriander seeds into a large bowl and mix well. Cover with plastic wrap and marinate for 24 hours.
The day after, remove the pork from the marinade, reserving the marinade. Pat dry with paper towel and lightly dust with flour. Heat the oil in a frypan and sear the meat until golden and transfer to a slow cooker.
Now pour in the marinade and crushed tomato and add the carrots, potatoes, pumpkin and celery. Season with salt and pepper then bring to the boil. Cover and cook on high for 4 hours. If sauce is too thin, mix some cornflour with a little water and stir through until right consistency is acquired. Serve on a bed of rice.