5 1/2 cups (about 2 pounds) Yukon Gold potatoes, cubed
vegetable cooking spray, as needed
1 cup (about 2 1/2 ounces) fresh shiitake mushroom caps, thinly sliced
2 cloves garlic, minced
1/2 cup rice wine vinegar
1/4 cup water
1 teaspoon Dijon mustard
1/2 teaspoon salt
1/4 teaspoon dried whole rosemary
1/4 teaspoon pepper
2 tablespoons olive oil
1/2 cup green onions, sliced
1. Place potatoes in large saucepan, cover with water, and bring to a boil. Cover, reduce heat, and simmer 8 minutes, or until tender. Drain, set aside.
2. Coat a small nonstick skillet with cooking spray; place over medium-high heat until hot. Add mushrooms, saute 3 minutes, add garlic, and saute 1 minute.
3. Stir in vinegar and next 5 ingredients (through pepper), and cook 3 minutes, or until liquid is reduced by 1/2. Remove from heat, stir in oil.
4. Combine potato and green onions in large bowl, stir well. Pour vinegar mixture over potato mixture, toss gently to coat. Serve warm. or cover and chill.