Chicken Potage

4 whole skinless chicken breasts
2 tsp low-sodium chicken bouillon granules
1 C grated raw potato
1 clove elephant garlic, thinly sliced
1 medium onion, chopped
1/2 C thinly sliced celery
1 C thinly sliced carrots
1 C thinly sliced fresh mushrooms
2 T chopped fresh parsley
1 tsp crushed rosemary
Freshly ground black pepper to taste
2 C skim milk
2 T cornstarch mixed with 3 T cold water
3/4 C green peas

Cook chicken in 2 qt water. Reserve 1-1/2 qt cooking liquid. Remove chicken from bones and dice. Add bouillon to cooking liquid. Simmer potato in 2 C of the broth until tender, about 15 minutes. Purée potato with liquid; stir into re-served broth. Add remaining vegetables and seasonings, except peas. Simmer, covered, until vegetables are tender. Add milk; stir in the cornstarch and water mixture. Add chicken and peas. Simmer until slightly thick, about 5 minutes.