Preheat oven to 400 degrees. Prick potatoes all around with a fork, rub with olive oil, and bake until done, about 1 hour and fifteen minutes. Allow potatoes to cool to room temperature, at least one hour. Preheat oven to 350 degrees. Saute onions in olive oil until translucent (about 4 minutes). Remove from heat. Use a large knife to cut the potatoes in half, lengthwise. Scoop out potatoes into a large bowl, creating potato skin shells, being extra careful not to break the skin. Beat potatoes together with the sauteed onions, milk, sour cream and salt. Once stuffing has reached the desired consistency (some like it lumpy), stir in cheese, and then spoon stuffing back into potato skin shells. Sprinkle generously with chili powder. Bake for 30 minutes. Makes 6 servings.
Per Serving: 281 Calories; 9g Fat (2g Sat, 5g Mono, 1g Poly); 7g Protein; 45g Carbohydrate; 4g Dietary Fiber; 7mg Cholesterol; 402mg Sodium. Food Exchanges: 2 1/2 Grains (Starch); 1 1/2 Fat.