Kale and Sausage Soup

1/4 cup olive oil
2 yellow onions, finely chopped
4 cloves garlic, minced
3 large russet potatoes, about 2 1/2 lb total weight, peeled and thinly sliced
6 cups chicken or vegetable stock
3/4 lb kielbasa or other cooked sausage, cut into slices 1/2 inch thick
1 bunch kale, thick stems and ribs removed, thinly sliced
Salt and freshly ground pepper
Extra-virgin olive oil for drizzling

In a large soup pot medium over heat, heat the olive oil. Add the onions and saute until lightly browned, 5 to 7 minutes. Add the garlic and cook for one minute longer. Add the potatoes, toss to coat, and saute for 2 minutes longer. Add the stock, cover, and bring to a boil. Reduce the heat to a simmer and cook until the potatoes are tender, about 20 minutes.

Add the sausage, cover and simmer until the sausage is heated through, about 5 minutes. Add the kale and cook, uncovered, until it is wilted but still bright green, 3 to 5 minutes. Season to taste with salt and pepper. Ladle into soup bowls and drizzle with extra-virgin olive oil.