Grilled potatoes

2 pounds baby red potatoes, large dice ½ cup sliced onions ½ cup sliced mushrooms 2 Tbsp margarine/butter 2 Tbsp vinegar, cider or balsamic 2 Tbsp water ¼ cup shredded cheddar cheese S & P to taste

Place potatoes & water in microwave safe container w/ lid. Microwave on high for 5 minutes, stirring midway. Add remaining ingredients, except cheese, and toss. Place on large sheet of foil. Fold all edges, making a packet. Place on grill to finish; 10-15 minutes. Slide onto heatproof platter, open and sprinkle cheese prior to serving.