Cook the bacon until it's crispy. Remove & set aside. Chop once it has cooled.
While the bacon is cooking add broth, clams with juice, potatoes, onion, celery, dill, parsley, salt, pepper & butter to the slow cooker. Cover and cook on high 3-4 hours or on low 5-6 hours.
During the last hour - add the half & half and the bacon.
In a separate bowl combine the milk and cornstarch, whisking well. Add to the soup and stir.
In the last ½ hour - add the potato flakes, ½ a cup at a time - waiting about 10 minutes before adding more until you reach the thickness you desire.
Hollow out the bread bowls by cutting a circle in the top. Pull off the piece you cut and then pull out more of the inside of the bread until it is deep enough to hold the chowder, but not to where it is thin along the bottom and sides.
Ladle out into bread bowls, top with some of the bread you removed from your bread bowl & enjoy.