In a large pot, cover potatoes with water and bring to a boil. Simmer for 18 to 20 minutes or until tender when pierced with a fork. Drain well and return to pot.

While potatoes are cooking, heat 1 tablespoon olive oil in a medium sauté pan over medium heat. Add onions and 1 teaspoon salt and sauté for 10 to 12 minutes or until softened and browned, stirring constantly.

Add onions to drained potatoes and mash with a potato masher until broken down but leaving some lumps. Stir in broth, garlic powder, remaining 4 tablespoons olive oil, and ¼ teaspoon salt.

Serve immediately or cover to keep warm.