In now empty stock pot, heat oil over medium heat. Add sliced leek and onion; sauté 10 minutes or until tender. Sprinkle flour over mixture; cook 1 minute, stirring constantly. Gradually add reserved stock, stirring until well- blended. Add potatoes and carrots. Juniper berries are edible, but if not interested in eating, tie them in a small piece of cheese cloth or place them in a tea ball and add to pot. Add salt, pepper, and bay leaves. Bring to a boil, reduce to simmer, covered, for 25 minutes or until vegetables are tender.