Polish Dill Pickle Soup (Zupa Ogorkowa)

olive oil

unsalted butter

small yellow onion, diced

garlic clove, minced

all-purpose flour

low-sodium chicken or vegetable stock

dill pickles (about 1 cup), finely chopped

liquid from pickle jar

large russet potatoes (about a pound), peeled and cut into 1/2-inch cubes

large carrots, peeled and diced

rib celery, diced

sour cream

dill

Old Bay seasoning

salt and pepper,