Heat the oil in a large saucepan set over medium heat. Add the onions; cook and stir for 6 to 9 minutes until onions begin to turn brown.
Add the garlic and rosemary; cook and stir for 1 minute longer.
Add the water, potatoes, ¾ teaspoon salt and ⅛ teaspoon black pepper. Bring to a low boil, reduce heat to low and simmer uncovered for 30 to 35 minutes until the potatoes are very tender. Using the back of a kitchen spoon, coarsely mash some of the potatoes.
Add the beans and kale to the soup; cook 4 to 7 minutes longer or until kale is wilted and tender.
Remove from heat and season to taste with additional salt and pepper, as desired.
