Method

Toss potatoes with olive oil, salt and rosemary. Spread in single layer on large parchment paper-lined baking sheet; roast in 425?‚ƒ‚‚ƒ‚ƒ‚‚ƒ‚ƒ‚‚ƒ‚ƒ‚šF (220?‚ƒ‚‚ƒ‚ƒ‚‚ƒ‚ƒ‚‚ƒ‚ƒ‚šC) oven for about 1 hour and 15 minutes or until tender and golden.

Dressing:
Meanwhile, finely chop onions, olives, tomatoes and capers; place in small bowl. Add garlic; set aside. In liquid measure, whisk vinegar with mustard, salt and pepper. Gradually whisk in oil in thin steady stream until thickened and blended. Whisk in olive mixture.(Make-ahead: Cover and refrigerate for up to 4 hours; bring to room temperature. Whisk to recombine.)

Toss potatoes with dressing and sprinkle with parsley. Serve warm.