Place the cored and partially peeled apples in a high-sided microwave-safe dish. Stuff the apples with orange rind strips and top each with 1/2 teaspoon margarine. Rub the pared flesh of the apple with lemon juice. Sprinkle with cinnamon and brown sugar substitute. Fill the dish with water 1/3 of the way up the sides of the apples. Cover with plastic wrap and cook in the microwave for 4 to 5 minutes on HIGH. Carefully remove the plastic wrap. Place the apples in individual serving bowls. Top each with 1 tablespoon (14 g) yogurt and sprinkle with some of the walnuts. Serve hot. Per serving: 145 calories (14% calories from fat), 2 g protein, 3 g total fat (0.3 g saturated fat), 32 g carbohydrates, 5 g dietary fiber, 0 cholesterol, 38 mg sodium Diabetic exchanges: 2 carbohydrate (fruit)