Drain juice from clams into a large, deep skillet over the onions, celery, potatoes and carrots. Add water to cover vegetables, and cook over medium heat until tender, about 30 minutes.
In a large, heavy saucepan, melt butter over medium heat. Whisk in flour until smooth. (Essentially, a very large roux.) Whisk in half-and-half, and stir constantly until thick and smooth. Heat through, but do not let it boil. Stir in vegetables and liquid.
Stir in clams just a few minutes before serving. If they cook too long they get tough. When clams are heated through, stir in vinegar, and season with salt and pepper. Good idea to make this a day ahead - it will naturally thicken overnight in the refrigerator.
Serve with oyster crackers or crusty bread on the side, or in a sourdough bread bowl.
Enjoy!
Notes
This recipe was created for Snow's New England. All opinions are my own.