1. Place potatoes in boiling water, and boil. This should take 20 minutes or so. They're done when you can stick a fork in them, they feel soft and slide right off. Drain and place into a large bowl.
2. In the meantime, put 2 tablespoons olive oil in a pan and heat onions, garlic, and rosemary on medium heat for 2-3 minutes. The point is not to brown them, just to bring the flavor out of the herbs and to de-intensify the strength of garlic and onions.
3. Add the garlic mixture to potatoes and add the stock and remaining olive oil. Mash until desired consistency is achieved. I like mine a little chunky. Add salt and pepper, to taste.
Enjoy!