Dill Pickle Soup

Ingredients

• vegetable oil and/or butter, for cooking
• 1 small onion, chopped
• 1-2 celery stalks, chopped
• 1-2 carrots, chopped
• 2 Tbsp all-purpose flour
• 1 L chicken or vegetable stock
• 4 large dill pickles, shredded or chopped
• 1/2 cup (ish) pickle brine, from the jar
• 2 small potatoes, halved and thinly sliced
• freshly ground black pepper
• sour cream and chopped fresh dill, for garnish (optional)