Add the butter and oilve oil to a large pot and set over medium-high heat. Add the leeks, carrots, and celery and sautee for about 5 minutes. Add the garlic and mushrooms and cook until the mushrooms start to release their juices.Add the butternut squash and the water and bring to a boil. Stir in the bouillon paste, then turn heat to medium-low, cover, and let simmer until the butternut is almost tender, about 15 minutes.Drain and rinse the beans and add them to the pot, followed by the barley. Mix in the spices, then cover again and let simmer for 10 minutes, until the barley is tender.Take about 2 Tbsp of the soup broth and mix it in a small bowl with the potato flour - this is to avoid clumps. Add to the soup and stir in. Finally, taste to see if more salt is needed (hint - if it tastes bland then it needs more salt). Add salt bit by bit until the flavors really pop - you shouldn't need much.Serve and enjoy!