In a large Dutch oven over medium heat, add the butter and allow to brown slightly (the butter will bubble and begin to smell nutty, about 2 minutes). Add the leeks and sauté for 6 minutes, until tender. Add the onions, shallots and celery to the leeks, stirring periodically for another 8 to 10 minutes. Add the garlic and cook for 1 minute more, seasoning with salt. Remove mixture from the pan, and place into a large bowl. Place the pan back over medium heat, and add the cut bacon (medium-thick pieces). Cook the bacon until the fat is rendered out and the bacon becomes slightly crispy on the edges. Using a slotted spoon, remove the bacon from the pan and add to the bowl with the leeks. Using a flat-edged spatula or other utensil, add the ground pork and break up any lumps of meat as it cooks, seasoning with the remaining salt.