In a small bowl, combine the garlic, rosemary, olive oil, and vinegar. Mix well. Using a pastry brush, cover both sides of the Portabello mushrooms with the mixture. Cover and refrigerate for 30 minutes.

Preheat the grill or oven broiler. Grill the mushrooms on low heat, or place them on a rack that is low in the oven. Cook each side of the Portabello for 5 minutes. Serve immediately.

This recipe yields 4 servings. Serving size: 1/2 Portabello cap.

Exchanges Per Serving: 1/2 Vegetable, 1/2 Fat.

Nutrition Facts: Calories 86; Calories from Fat 61; Fat 6g; Saturated Fat 0g; Cholesterol 0mg; Sodium 9mg; Carbohydrates 6g; Dietary Fiber 2g; Sugars 1g; Protein 2g.