Caramelize onion in olive oil with sugar and salt in a heavy skillet over medium low-heat. Stir occasionally to prevent scorching, but do not stir too often. They will brown better if left alone. After 5 minutes of cooking, cover the pan (the lid keeps moisture inside so the onions won't burn easily). Cook until brown and very soft, 20-25 minutes. Stir in the port, scraping up any brown residue left on the bottom of the pan; cool onions slightly.
2 cups yellow onion, chopped, 1 tbsp olive oil, pinch of sugar, pinch of salt, 2 tbsp Port
Blend cheese, yogurt, mayonnaise, Worcestershire and lemon juice in a bowl.
4 oz blue cheese, crumbled (about 2/3 cup), 6 oz plain low-fat Greek or nonfat Greek yogurt, 1/2 cup mayonnaise, 1 tsp Worcestershire sauce, juice of 1/2 a lemon
Add cooled onions, scallions, salt and cayenne to taste; stir to blend. Cover and chill at least 2 hours, but 24 hours is preferred. The dip really changes flavor over that time.
2 tbsps scallions, chopped, salt and cayenne pepper to taste
Serve with potato chips or spread it on your favorite burger.