Heat a Dutch oven over medium heat. Add oil to pan; swirl to coat. Add leek; saute 10 minutes or until tender. Add oyster, cremini and shitake mushrooms; cook 15 minutes or until tender, stirring occasionally. Add barley and garlic; cook 2 minutes or until slightly toasted, stirring frequently. Add wine and 1 tsp. thyme; simmer 1 minute or until liquid is nearly absorbed. Add 8 cups water and porcini mushrooms. Reduce heat and simmer 1 hour or until barley is tender and creamy, stirring frequently. Stir in cheese, salt and pepper. Sprinkle with remaining 1 tsp. thyme. Serve immediately.