Drain the clams, adding the juice from the cans to a large stock pot. Set the clams aside.
Add chicken broth and diced potatoes to the pot (the liquid should just barely cover the potatoes). Bring to a simmer, add the bay leaf, and cook until the potatoes are barely fork tender, about 5-6 minutes.
While the potatoes cook, in a second pot, heat the butter and olive oil over medium heat until the butter is melted. Add the onions, celery, bell peppers and garlic and cook until tender, about 4-5 minutes.
Stir in the flour and cook for 30 seconds. Gradually stir in the milk and half and half, whisking as you add them to break up any clumps of flour. Bring mixture to a simmer and cook until the thickened, about 5 minutes.
Stir the creamy mixture into the potatoes. Stir in the salt, pepper, vinegar, and reserved clams. Cook for 5 more minutes.
Video
Notes
Make Ahead Instructions: The vegetables can all be chopped ahead of time to make dinner time even quicker, or make the entire soup ahead of time and store in refrigerator until ready to eat.Freezing Instructions: I generally do not freeze soups with potatoes in them because the potatoes can get soft and mushy (however, some people don't mind). Creamy soups can also have a slightly different texture once thawed.