Heat 1 TBS broth in a 10-12 inch stainless steel skillet. Healthy Sauté onion for 5 minutes over medium heat stirring frequently. While onions are cooking, prepare rest of ingredients.
Add garlic, mushrooms and rosemary to onions, and continue to sauté for another 5 minutes.
Stir in port and simmer for about 4 more minutes. Season with salt and pepper.