Clam chowder is a type of soup that originated in New England and is made with clams, broth or milk, potatoes, onions, and other ingredients such as bacon or salt pork. It can also include seasonings like thyme or bay leaves.
Heat a large skillet over medium heat. Add onions, celery, and potatoes. Drain the clam juice, then add it along with water to the skillet. Cook for 15 minutes, then remove from heat and set aside.
In a separate saucepan, melt the butter. Add all-purpose flour, whisking until smooth. Gradually stir in the cream, continuing to whisk constantly. Cook for an additional 5 minutes.
Combine the cooked vegetables and clam juice mixture with the contents of the saucepan. Simmer for another 5 minutes.