Chicken and Spring Vegetable Soup

Name: Chicken and Spring Vegetable Soup
Ingredients: 1 Tbs. olive oil; 1 yellow onion, diced; 2 celery stalks, diced; 2 carrots, diced; 1 large garlic clove, minced; 1 Tbs. chicken demi-glace; 12 cups (3 l) water; 2 boneless, skinless chicken breast halves, each about 6 oz. (185 g); 6 large fresh flat-leaf parsley sprigs; 1 bay leaf; Kosher salt and freshly ground pepper, to taste; 1/4 lb. (125 g) cremini mushrooms, thinly sliced; 1/2 bunch asparagus, thinly sliced on the bias; 1 cup (5 oz./155 g) fresh or thawed frozen peas