Peel the potatoes and cut into ½-inch thick slices or wedges.
Heat the vegetable oil in a large, non-stick skillet over medium heat and add the potatoes.
Season the potatoes with salt, pepper, and red pepper flakes. Add the vegetable broth, lemon juice, and rosemary springs. Cover with a tight lid and cook for 15 minutes, or until the liquid is almost gone.
Remove the lid and keep cooking the potatoes, stirring occasionally, allowing them to brown and fully cook through.
Add the garlic, if desired, and cook for 1 more minute. Garnish with fresh rosemary and serve immediately.