1 1/2 lb. small red skinned potatoes with skins, quartered
1/2 lb. green beans, trimmed and cut into 1 1/2-inch pieces
1 onion, chopped
2 tbsp. oil
1/4 c. Dijon mustard
3 tbsp. white vinegar
1/2 tsp. salt
1 tbsp. sugar
1/8 tsp. pepper

Cook potatoes in lightly salted boiling water for 15 minutes or until tender. Add the green beans for the last 5 minutes of cooking.

Meanwhile, sauté onion in oil over medium heat for 10 minutes or until softened. Remove from heat. Whisk in mustard, vinegar, sugar, salt and pepper. Drain potatoes and green beans. Toss in serving bowl with mustard vinaigrette. Serve warm.