Use a sharp knife or mandoline to remove the corn niblets from the cob. Reserve both the niblets and the cob.
Trim the leeks.Slice the leek, lengthwise in half and wash to remove any dirt between the leaves. Slice the dark green part off the leeks, reserving both green and white parts.
To a stockpot, add the corn cobs, chicken stock, coriander seeds, peppercorns and only the green parts of the leeks. Bring to a simmer and cover. Cook for 15-20 minutes.
In the meantime, cut the white portion of the leeks into quarter inch half moons.
To a second large pot, set over medium heat, add the bacon. Cook for about 10 minutes, stirring occasionally until the bacon has rendered its fat and is crispy. Remove the bacon with a slotted spoon to a paper towel lined plate. Leave about 2 tablespoons of bacon fat in the pot.
Add the white leeks and celery to the bacon fat and sweat them down for about 10 minutes until soft and translucent. Add the corn niblets, garlic, thyme and cayenne and cook for another two minutes. Sprinkle the flour over the vegetables and cook for about 2 minutes, stirring occasionally. Add the potatoes.
Place a large colander over the pot with the vegetables and strain the chicken stock into the pot. Discard the corn cobs and leeks etc. Bring to a simmer, cover and cook for 15 minutes or until the potatoes are tender.
Use an immersion blender and blitz for about 10 seconds - leaving a good amount of vegetables chunky and intact. Stir in the half and half cream. Bring back to the simmer.
Stir in half the green onions. Turn off the heat.
Serve, garnished with bacon bits and more green onions.
