Savory Roast Potatoes

3 1/2 pounds medium size red (new) potatoes, cut into quarters
1 medium onion, minced
1/4 cup extra virgin olive oil
1 tsp salt
2 tsp dried rosemary
3/4 tsp pepper

Heat oven to 400F
Toss above ingredients together until well coated
Layer in baking pan
Roast 40-45 minutes turning twice until tender and golden